Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 24
Filter
1.
QJM ; 112(11): 841-846, 2019 Nov 01.
Article in English | MEDLINE | ID: mdl-31286139

ABSTRACT

BACKGROUND: The relationship between gout medication use and cataract development is controversial. Moreover, limited clinical studies have evaluated this relationship. AIM: To assess the effects of colchicine, allopurinol and benzbromarone on the risk of cataract in patients with gout. DESIGN: Population-based nested case-control study. METHODS: We enrolled 7900 patients who had received a new diagnosis of cataract >3 years after gout diagnosis into the study group and 33 475 patients who did not receive a diagnosis of cataract into the control group by matching for age, sex and the year of gout diagnosis at a ratio of 1:1. We used World Health Organization's defined daily dose (DDD) as a measure to assess the dosage of colchicine, allopurinol and benzbromarone exposure. Logistic regression was used to estimate crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of cataract. RESULTS: The risk of cataract significantly increased in patients who received colchicine at a cumulative DDD of ≥66.5 (OR = 1.17, 95% CI = 1.01-1.36, P = 0.041). In the age-stratified analysis, patients with gout aged >60 years had a higher risk of cataract (OR = 1.27, 95% CI = 1.06-1.53, P = 0.011) than did patients aged <60 years. Allopurinol and benzbromarone had no association with cataract. CONCLUSIONS: In this population-based nested case-control study, we observed that colchicine use increased the risk of cataract in patients with gout, especially in those aged >60 years who received colchicine at a cumulative DDD of >66.5.


Subject(s)
Cataract/chemically induced , Colchicine/adverse effects , Gout Suppressants/adverse effects , Gout/drug therapy , Adult , Age Factors , Aged , Aged, 80 and over , Allopurinol/therapeutic use , Benzbromarone/therapeutic use , Case-Control Studies , Cataract/epidemiology , Colchicine/administration & dosage , Databases, Factual , Female , Gout/complications , Gout Suppressants/administration & dosage , Humans , Logistic Models , Male , Middle Aged , National Health Programs , Risk Factors , Taiwan , Young Adult
3.
Anaesthesia ; 71(1): 31-8, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26460721

ABSTRACT

In patients with limited mouth opening, traditional laryngoscopy and videolaryngoscopes are not useful when performing nasotracheal intubation. Eighty patients with limited mouth opening who required nasotracheal intubation were randomly assigned to either fibreoptic intubation (n = 40) or the Trachway(®) (n = 40). Using the modified nasal intubation difficulty scale, 22 (55%) patients who received fibreoptic intubation were categorised as no difficulty compared with 40 (100%) patients in the Trachway group (p < 0.001). Mean (SD) total intubation time was 71.8 (23.3) s in patients who received fibreoptic intubation compared with 35.4 (9.8) s in the Trachway group (p < 0.001). We conclude that the Trachway technique for nasotracheal intubation is quicker and easier compared with fibreoptic intubation in patients with limited mouth opening.


Subject(s)
Intubation, Intratracheal/methods , Video Recording/instrumentation , Adult , Aged , Female , Fiber Optic Technology , Humans , Intubation, Intratracheal/instrumentation , Male , Middle Aged , Mouth , Time Factors
5.
Mol Psychiatry ; 19(5): 536-43, 2014 May.
Article in English | MEDLINE | ID: mdl-24589887

ABSTRACT

Converging epidemiological studies indicate that cannabis abuse during adolescence increases the risk of developing psychosis and prefrontal cortex (PFC)-dependent cognitive impairments later in life. However, the mechanisms underlying the adolescent susceptibility to chronic cannabis exposure are poorly understood. Given that the psychoactive constituent of cannabis binds to the CB1 cannabinoid receptor, the present study was designed to determine the impact of a CB1 receptor agonist (WIN) during specific windows of adolescence on the functional maturation of the rat PFC. By means of local field potential recordings and ventral hippocampal stimulation in vivo, we found that a history of WIN exposure during early (postnatal days - P35-40) or mid-(P40-45) adolescence, but not in late adolescence (P50-55) or adulthood (P75-80), is sufficient to yield a state of frequency-dependent prefrontal disinhibition in adulthood comparable to that seen in the juvenile PFC. Remarkably, this prefrontal disinhibition could be normalized following a single acute local infusion of the GABA-Aα1 positive allosteric modulator Indiplon, suggesting that adolescent exposure to WIN causes a functional downregulation of GABAergic transmission in the PFC. Accordingly, in vitro recordings from adult rats exposed to WIN during adolescence demonstrate that local prefrontal GABAergic transmission onto layer V pyramidal neurons is markedly reduced to the level seen in the P30-35 PFC. Together, these results indicate that early and mid-adolescence constitute a critical period during which repeated CB1 receptor stimulation is sufficient to elicit an enduring state of PFC network disinhibition resulting from a developmental impairment of local prefrontal GABAergic transmission.


Subject(s)
Benzoxazines/pharmacology , Central Nervous System Agents/pharmacology , Morpholines/pharmacology , Naphthalenes/pharmacology , Prefrontal Cortex/drug effects , Prefrontal Cortex/growth & development , Receptor, Cannabinoid, CB1/agonists , gamma-Aminobutyric Acid/metabolism , Animals , Benzodiazepines/pharmacology , Electric Stimulation , GABA Modulators/pharmacology , Hippocampus/drug effects , Hippocampus/growth & development , Hippocampus/physiology , Inhibitory Postsynaptic Potentials/drug effects , Inhibitory Postsynaptic Potentials/physiology , Male , Neurons/drug effects , Neurons/physiology , Patch-Clamp Techniques , Piperidines/pharmacology , Prefrontal Cortex/physiology , Pyramidal Cells/drug effects , Pyramidal Cells/growth & development , Pyramidal Cells/physiology , Pyrazoles/pharmacology , Random Allocation , Rats, Sprague-Dawley , Receptor, Cannabinoid, CB1/metabolism , Receptors, GABA-A/metabolism , Synaptic Transmission/drug effects , Synaptic Transmission/physiology , Thiophenes/pharmacology
6.
Anaesthesia ; 68(8): 851-5, 2013 Aug.
Article in English | MEDLINE | ID: mdl-24044439

ABSTRACT

We compared direct laryngoscopy with a Macintosh blade vs indirect bronchoscopy with a Trachway® stylet, for endobronchial intubation with a left-sided double-lumen tube. We allocated participants scheduled for thoracic surgery and who had normal predicted laryngoscopy, 30 to each group. The mean (SD) intubation times with laryngoscope and Trachway were 48 (11) s vs 28 (4) s, respectively, p < 0.001. The rates of hoarseness on the first postoperative day, categorised as none/mild/moderate/severe, were 10/12/7/1 and 22/6/2/0, respectively, p = 0.008, without differences on subsequent days. Left endobronchial intubation with a double-lumen tube is slower using direct laryngoscopy and causes more hoarseness than indirect bronchoscopy with a Trachway stylet.


Subject(s)
Intubation, Intratracheal/methods , Laryngoscopes , Laryngoscopy/methods , Adult , Anesthesia, Inhalation , Blood Pressure/physiology , Female , Heart Rate/physiology , Hoarseness/epidemiology , Hoarseness/etiology , Humans , Male , Methyl Ethers , Middle Aged , Monitoring, Intraoperative , Pharyngitis/epidemiology , Pharyngitis/etiology , Postoperative Complications/epidemiology , Sevoflurane , Video Recording
7.
Anaesthesia ; 67(4): 411-5, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22324297

ABSTRACT

Intubation with a double-lumen tube is important for achieving one-lung ventilation and facilitating thoracic surgery. The GlideScope(®) videolaryngoscope (Verathon Inc., Bothell, WA, USA) is designed to assist tracheal intubation for patients with a difficult airway. We wished to compare the GlideScope and direct laryngoscopy for double-lumen tube intubation. Sixty adult patients requiring a double-lumen tube for thoracic surgery and predicted uncomplicated laryngoscopy were randomly assigned to a direct Macintosh laryngoscopy group (n = 30) or a GlideScope group (n = 30). The mean (SD) duration of intubation was longer in the Macintosh group (62.5 (29.7) s) than in the GlideScope group (45.6 (10.7) s; p = 0.007). There was no difference in the success of the first attempt at intubation (26/30 (87%) and 30/30 (100%) for Macintosh and GlideScope groups, respectively; p = 0.112). The incidence of sore throat and hoarseness was higher in the Macintosh group (18 (60%) and 14 (47%), respectively) than in the GlideScope group (6 (20%) and 4 (13%), respectively; p = 0.003 and 0.004). We conclude that double-lumen tube intubation in patients with predicted normal laryngoscopy is easier using the GlideScope videolaryngoscope than the Macintosh laryngoscope.


Subject(s)
Intubation, Intratracheal/instrumentation , Laryngoscopes , Laryngoscopy/instrumentation , Video Recording , Adult , Equipment Design , Female , Humans , Male
9.
Biosens Bioelectron ; 21(8): 1631-7, 2006 Feb 15.
Article in English | MEDLINE | ID: mdl-16343891

ABSTRACT

In clinical practices, the examination of pentamer C-reactive protein (pCRP) is commonly used as a prognostic indicator of the risk of a patient developing cardiovascular disease (CVD). Structural modification of pCRP produces a modified CRP (mCRP) which exhibits different biological activities in the body. In recent years, mCRP has come to be regarded as a more powerful inducer than pCRP, and hence mCRP measurement has emerged as an important indicator for assessing the risk of developing CVD. The surface plasmon resonance (SPR) biosensing technique can be employed to increase the detection accuracy and real-time response when sensing pCRP or mCRP. In this study, three monoclonal antibodies (Mabs), C8, 8D8, and 9C9, are immobilized on a protein G layer for subsequent CRP detection. The experimental results reveal that the Mab C8 reacts with both pCRP and mCRP, the Mab 8D8 with pCRP, and the Mab 9C9 with mCRP. No false signals caused by non-specific binding are observed. When detecting pCRP using Mab C8, the SPR bioassay provides sufficient sensitivity to evaluate whether or not a patient is at risk of developing CVD. SPR biosensing provides a viable and accurate approach for the real-time evaluation of pCRP and mCRP levels, and is therefore of considerable benefit in clinical examinations of CPR.


Subject(s)
Antibodies, Monoclonal/analysis , Biosensing Techniques/instrumentation , C-Reactive Protein/analysis , Immunoassay/instrumentation , Surface Plasmon Resonance/instrumentation , Antibodies, Monoclonal/immunology , Biosensing Techniques/methods , C-Reactive Protein/immunology , Equipment Design , Equipment Failure Analysis , Immunoassay/methods , Reproducibility of Results , Sensitivity and Specificity , Surface Plasmon Resonance/methods
10.
Neuroscience ; 123(2): 293-8, 2004.
Article in English | MEDLINE | ID: mdl-14698740

ABSTRACT

Recent in vivo electrophysiological studies suggest that chronic dopamine depletion alters profoundly the firing pattern of basal ganglia neurons. These changes may disrupt the processing of cortical information flow from the striatum to the output nuclei, and presumably underlie the clinical manifestations of Parkinson's disease. We have recently reported that chronic nigrostriatal lesions induce changes in the functional state of striatal medium-spiny neurons (MSNs) that could facilitate spreading of cortical synchronous activity (approximately 1 Hz) to striatal target nuclei. Here we show that systemic administration of D1 dopamine agonists was sufficient to restore the changes induced by chronic nigrostriatal lesions on striatal neuronal activity into the normal state. Following systemic administration of SKF38393 or SKF81279 the membrane potential of striatal MSNs was upheld into a more hyperpolarized value and action potential firing probability decreased. D1 agonists also increased the latency to the cortically driven plateau depolarization and reduced the peak potential of the short latency depolarizing postsynaptic response to a more hyperpolarized value. The present study provides in vivo evidence indicating that pharmacological stimulation of D1-class dopamine receptors can modulate the flow of cortical information through the striatum in the parkinsonian state.


Subject(s)
Cerebral Cortex/physiology , Corpus Striatum/physiology , Dopamine Agonists/pharmacology , Neurons/metabolism , Parkinsonian Disorders/physiopathology , Receptors, Dopamine D1/physiology , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology , Animals , Cerebral Cortex/drug effects , Corpus Striatum/drug effects , Electrophysiology , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/physiology , Immunohistochemistry , Membrane Potentials/drug effects , Membrane Potentials/physiology , Neurons/drug effects , Rats , Receptors, Dopamine D1/drug effects
11.
Cell Mol Neurobiol ; 22(5-6): 611-32, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12585682

ABSTRACT

1. The striatum is part of a multisynaptic loop involved in translating higher order cognitive activity into action. The main striatal computational unit is the medium spiny neuron, which integrates inputs arriving from widely distributed cortical neurons and provides the sole striatal output. 2. The membrane potential of medium spiny neurons' displays shifts between a very negative resting state (down state) and depolarizing plateaus (up states) which are driven by the excitatory cortical inputs. 3. Because striatal spiny neurons fire action potentials only during the up state, these plateau depolarizations are perceived as enabling events that allow information processing through cerebral cortex-basal ganglia circuits. In vivo intracellular recording techniques allow to investigate simultaneously the subthreshold behavior of the medium spiny neuron membrane potential (which is a "reading" of distributed patterns of cortical activity) and medium spiny neuron firing (which is an index of striatal output). 4. Recent studies combining intracellular recordings of striatal neurons with field potential recordings of the cerebral cortex illustrate how the analysis of the input-output transformations performed by medium spiny neurons may help to unveil some aspects of information processing in cerebral cortex-basal ganglia circuits, and to understand the origin of the clinical manifestations of Parkinson's disease and other neurologic and neuropsychiatric disorders that result from alterations in dopamine-dependent information processing in the cerebral cortex-basal ganglia circuits.


Subject(s)
Biological Clocks/physiology , Dopamine/metabolism , Neostriatum/metabolism , Neural Pathways/metabolism , Neurons/metabolism , Action Potentials/physiology , Animals , Dendrites/metabolism , Humans , Neostriatum/cytology , Neural Pathways/cytology , Neurons/cytology , Parkinson Disease/metabolism , Parkinson Disease/physiopathology , Synaptic Transmission/physiology
12.
Brain Res ; 904(1): 93-103, 2001 Jun 15.
Article in English | MEDLINE | ID: mdl-11516415

ABSTRACT

Single unit recordings performed in animal models of Parkinson's disease revealed that output nuclei neurons display modifications in firing pattern and firing rate, which are supposed to give rise to the clinical manifestations of the illness. We examined the activity pattern of single units from the substantia nigra pars reticulata, the main output nuclei of the rodent basal ganglia, in urethane-anesthetized control and 6-hydroxydopamine-lesioned rats (a widespread model of Parkinson's disease). We further studied the effect of a subthalamic nucleus lesion in both experimental groups. Subthalamic nucleus lesion produces behavioral improvement in animal models of Parkinson's disease, and was expected to reverse the changes induced by 6-hydroxydopamine lesions. A meticulous statistical investigation, which included a non-biased classification of the recorded units by means of cluster analysis, allowed us to identify a low frequency oscillation of firing rate ( approximately 0.9 Hz) occurring in approximately 35% of the units recorded from 6-hydroxydopamine-lesioned rats, as the main feature differentiating 6-hydroxydopamine-lesioned and control rats. Subthalamic nucleus lesions significantly reduced the proportion of oscillatory units in 6-hydroxydopamine-lesioned rats. However, the population of nigral units recorded from rats bearing both lesions still differed significantly from control units. These results suggest that oscillatory activity in the basal ganglia output nuclei may be related to some clinical features of parkinsonism, and suggest a putative mechanism through which therapeutic interventions aimed at modifying subthalamic nucleus function produce clinical benefit in Parkinson's disease.


Subject(s)
Action Potentials/physiology , Biological Clocks , Neural Pathways/physiology , Neurons/physiology , Parkinson Disease/physiopathology , Substantia Nigra/physiology , Subthalamic Nucleus/physiology , Action Potentials/drug effects , Animals , Disease Models, Animal , Excitatory Amino Acid Agonists/pharmacology , Kainic Acid/pharmacology , Male , Nerve Degeneration/chemically induced , Nerve Degeneration/pathology , Nerve Degeneration/physiopathology , Neural Pathways/cytology , Neural Pathways/drug effects , Neurons/cytology , Neurons/drug effects , Neurotoxins/pharmacology , Oxidopamine/pharmacology , Parkinson Disease/pathology , Rats , Rats, Sprague-Dawley , Substantia Nigra/cytology , Substantia Nigra/drug effects , Subthalamic Nucleus/cytology , Subthalamic Nucleus/drug effects , Sympatholytics/pharmacology
13.
J Neurosci ; 21(16): 6430-9, 2001 Aug 15.
Article in English | MEDLINE | ID: mdl-11487667

ABSTRACT

Neurons in the basal ganglia output nuclei display rhythmic burst firing after chronic nigrostriatal lesions. The thalamocortical network is a strong endogenous generator of oscillatory activity, and the striatum receives a massive projection from the cerebral cortex. Actually, the membrane potential of striatal projection neurons displays periodic shifts between a very negative resting potential (down state) and depolarizing plateaus (up states) during which they can fire action potentials. We hypothesized that an increased excitability of striatal neurons may allow transmission of cortical slow rhythms through the striatum to the remaining basal ganglia in experimental parkinsonism. In vivo intracellular recordings revealed that striatal projection neurons from rats with chronic nigrostriatal lesions had a more depolarized membrane potential during both the down and up states and an increased firing probability during the up events. Furthermore, lesioned rats had significantly fewer silent neurons than control rats. Simultaneous recordings of the frontal electrocorticogram and membrane potential of striatal projection neurons revealed that the signals were oscillating synchronously in the frequency range 0.4-2 Hz, both in control rats and rats with chronic nigrostriatal lesions. Spreading of the slow cortical rhythm is limited by the very low firing probability of control rat neurons, but a slow oscillation is well reflected in spike trains of approximately 60% of lesioned rat neurons. These findings provide in vivo evidence for a role of dopamine in controlling the flow of cortical activity through the striatum and may be of outstanding relevance for understanding the pathophysiology of Parkinson's disease.


Subject(s)
Biological Clocks , Cerebral Cortex/physiopathology , Membrane Potentials , Neurons , Parkinson Disease, Secondary/physiopathology , Action Potentials , Animals , Corpus Striatum/drug effects , Corpus Striatum/pathology , Corpus Striatum/physiopathology , Electric Stimulation , Frontal Lobe/physiopathology , Male , Neurons/physiology , Oxidopamine , Parkinson Disease, Secondary/chemically induced , Parkinson Disease, Secondary/pathology , Periodicity , Rats , Rats, Sprague-Dawley , Reaction Time , Signal Processing, Computer-Assisted , Substantia Nigra/drug effects , Substantia Nigra/pathology , Substantia Nigra/physiopathology
14.
Brain Res Mol Brain Res ; 80(1): 1-6, 2000 Aug 14.
Article in English | MEDLINE | ID: mdl-11039723

ABSTRACT

The orphan nuclear receptor Nurr1 is critical for the survival of mesencephalic dopaminergic precursor neurons. Little is known about the mechanisms that regulate Nurr1 expression in vivo. Other members of this receptor family have been shown to be activated by dopamine. We sought to determine if Nurr1 expression is also regulated by endogenous dopamine through dopamine receptors. Consequently, we investigated the expression of Nurr1 mRNA in genetically modified mice lacking both functional copies of the D2 dopamine receptor gene and in their congenic siblings. Quantitative in situ hybridization demonstrated a significant increased expression of Nurr1 mRNA in the substantia nigra pars compacta and the ventral tegmental area of D2 dopamine receptor -/- mice. No change in Nurr1 expression was detected in other brain regions, such as the habenular nuclei and temporal cortex. Among the cell groups studied, mesencephalic dopaminergic neurons are unique in that they express both Nurr1 and the D2 dopamine receptor, and synthesize dopamine. Thus, it seems plausible that the selective increase in Nurr1 expression observed in D2 receptor-deficient mice is the consequence of an impaired dopamine autoreceptor function.


Subject(s)
DNA-Binding Proteins , Mesencephalon/metabolism , Nerve Tissue Proteins/genetics , Neurons/metabolism , RNA, Messenger/metabolism , Receptors, Dopamine D2/physiology , Transcription Factors/genetics , Animals , In Situ Hybridization , Mice , Nuclear Receptor Subfamily 4, Group A, Member 2 , Receptors, Dopamine D2/biosynthesis , Receptors, Dopamine D3 , Substantia Nigra/cytology
15.
Neuroscience ; 99(4): 643-50, 2000.
Article in English | MEDLINE | ID: mdl-10974427

ABSTRACT

Recent pathophysiological models of basal ganglia function in Parkinson's disease predict that specific neurochemical changes in the indirect pathway would follow the lack of stimulation of D(2) dopamine receptors. Post mortem studies of the basal ganglia in genetically modified mice lacking functional copies of the D(2) dopamine receptor gene allowed us to test these predictions. When compared with their congenic N(5) wild-type siblings, mice lacking D(2) receptors show an increased expression of enkephalin messenger RNA in the striatum, and an increased activity and expression of cytochrome oxidase I in the subthalamic nucleus, as expected. In addition, D(2) receptor-deficient mice display a reduced expression of glutamate decarboxylase-67 messenger RNA in the globus pallidus, as the basal ganglia model predicts. This reduction contrasts with the lack of change or increase in glutamate decarboxylase-67 messenger RNA expression found in animals depleted of dopamine after lesions of the mesostriatal dopaminergic system. Furthermore, D(2) receptor-deficient mice show a significant decrease in substance P messenger RNA expression in the striatonigral neurons which form the direct pathway. Finally, glutamate decarboxylase-67 messenger RNA expression in the basal ganglia output nuclei was not affected by mutations in the D(2) receptor gene, a fact that could probably be related to the absence of a parkinsonian locomotor phenotype in D(2) receptor-deficient mice. In summary, these findings provide compelling evidence demonstrating that the lack of endogenous stimulation of D(2) receptors is sufficient to produce subthalamic nucleus hyperactivity, as assessed by cytochrome oxidase I histochemistry and messenger RNA expression, and strongly suggest the existence of interactions between the basal ganglia direct and indirect pathways.


Subject(s)
Globus Pallidus/cytology , Neostriatum/cytology , Receptors, Dopamine D2/genetics , Substantia Nigra/cytology , Subthalamic Nucleus/cytology , Animals , Electron Transport Complex IV/analysis , Electron Transport Complex IV/genetics , Female , Gene Expression/physiology , Globus Pallidus/chemistry , Glutamate Decarboxylase/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neostriatum/chemistry , Neural Pathways , Neurons/chemistry , Neurons/enzymology , Parkinson Disease/pathology , Phenotype , RNA, Messenger/analysis , Substance P/genetics , Substantia Nigra/chemistry , Subthalamic Nucleus/chemistry
16.
Eur J Neurosci ; 12(1): 247-56, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10651879

ABSTRACT

In order to increase our understanding of Parkinson's disease pathophysiology, we studied the effects of intrastriatally administered selective dopamine receptor agonists on single units from the substantia nigra pars reticulata of 6-hydroxydopamine (6-OHDA)-lesioned rats with or without an additional subthalamic nucleus lesion. Nigral pars reticulata units of 6-OHDA-lesioned rats were classified into two types, showing regular and bursting discharge patterns, respectively ('non-burst' and 'burst' units). Non-burst and burst units showed distinct responses to intrastriatal quinpirole (the former were excited and burst units inhibited). Furthermore, subthalamic nucleus lesions significantly decreased the number of nigral units showing a spontaneous bursting pattern, and reduced the proportion of units that responded to quinpirole. In contrast, subthalamic lesions did not alter the proportion of nigral units that responded to SKF38393, although the lesions changed some response features, e.g. response type and magnitude. Burst analysis showed that quinpirole did not modify the discharge pattern of burst units, whereas SKF38393 produced a shift to regular firing in 62% of the burst units tested. In conjunction, our results support that: (i) the subthalamic nucleus has an important influence on output nuclei firing pattern; (ii) striatal D2 receptors have a strong influence on nigral firing rate, and a less relevant role in controlling firing pattern; (iii) burst and non-burst units differ in their response to selective stimulation of striatal dopamine receptors; (iv) the effects of striatal D2 receptors on nigral units are mainly, though not exclusively, mediated by the subthalamic nucleus; and (v) nigral responses to SKF38393 involve the subthalamic nucleus.


Subject(s)
Corpus Striatum/physiology , Neurons/physiology , Receptors, Dopamine D2/physiology , Substantia Nigra/physiology , Subthalamic Nucleus/physiology , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology , Animals , Benzazepines/pharmacology , Dopamine Antagonists/pharmacology , Kainic Acid/toxicity , Male , Neurons/drug effects , Oxidopamine/toxicity , Quinpirole/pharmacology , Rats , Rats, Sprague-Dawley , Salicylamides/pharmacology , Substantia Nigra/drug effects , Subthalamic Nucleus/drug effects
17.
Neuroreport ; 8(3): 783-7, 1997 Feb 10.
Article in English | MEDLINE | ID: mdl-9106767

ABSTRACT

After intrastriatal administration of selective dopamine receptor agonists only a small percentage of substantia nigra pars reticulata single units showed changes in firing rate (23% after SKF38393 and 17% after quinpirole). After their intrastriatal co-administration, however, or after the application of the non-selective dopamine receptor agonist apomorphine, 72% and 69% of units responded, respectively. This result confirms the participation of the striatum in the phenomenon of D1-D2 receptor interaction, and show that co-activation of both receptor subtypes produced a maximal effect on basal ganglia output nuclei.


Subject(s)
2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology , Corpus Striatum/physiology , Dopamine Agonists/pharmacology , Receptors, Dopamine D1/physiology , Receptors, Dopamine D2/physiology , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/administration & dosage , Animals , Apomorphine/administration & dosage , Apomorphine/pharmacology , Corpus Striatum/drug effects , Dopamine Agonists/administration & dosage , Electrophysiology/methods , Evoked Potentials/drug effects , Male , Microinjections , Neurons/drug effects , Neurons/physiology , Quinpirole/administration & dosage , Quinpirole/pharmacology , Rats , Rats, Sprague-Dawley , Substantia Nigra/drug effects , Substantia Nigra/physiology
18.
Synapse ; 27(4): 278-93, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9372551

ABSTRACT

The spontaneous activity and the response to intrastriatal application of apomorphine of substantia nigra pars reticulata (SNpr) single units was studied in four experimental groups of rats: (1) normal rats; (2) subthalamic nucleus (STN) lesioned rats; (3) rats bearing a 6-hydroxydopamine (60HDA) lesion; and (4) 60HDA-lesioned animals with an additional STN lesion. Thirty-eight percent of units from 60HDA-lesioned rats showed a bursting pattern of spontaneous activity, which was never found in normal rats. STN lesions had no effect on the spontaneous activity of SNpr units from normal rats, but reduced the percentage of burst units in 60HDA-lesioned animals. Intrastriatal apomorphine produced responses in 62% of SNpr units from normal rats and 85% of units from 60HDA-lesioned animals (P < 0.05). In addition, the modifications in the firing rate and in the coefficient of variation of the interspike intervals induced by intrastriatal apomorphine were significantly greater for the units isolated from 60HDA-lesioned rats. In particular, it was noted that all the burst units responded to apomorphine, showing the highest changes in firing rate and coefficient of variation. However, intrastriatal apomorphine did not always turn the activity of burst units into a more physiological pattern. STN lesions reduced the percentage of units responding to intrastriatal apomorphine in normal rats. In 60HDA-lesioned rats, STN lesions reduced the number of responsive units, and their change in mean firing rate and coefficient of variation. Our results show that the STN participates in the genesis of the bursting pattern of activity of SNpr units in 60HDA-lesioned rats, and that STN lesions can partially revert the abnormal spontaneous and apomorphine-induced responses of SNpr units in these animals.


Subject(s)
Apomorphine/pharmacology , Corpus Striatum/drug effects , Dopamine Agonists/pharmacology , Neurons/drug effects , Substantia Nigra/drug effects , Thalamic Nuclei/drug effects , Animals , Kainic Acid/pharmacology , Male , Neurotoxins , Oxidopamine , Rats , Rats, Sprague-Dawley , Reference Values , Substantia Nigra/cytology , Substantia Nigra/pathology
19.
Opt Lett ; 21(3): 180-2, 1996 Feb 01.
Article in English | MEDLINE | ID: mdl-19865345

ABSTRACT

Degenerate (single-color) and nondegenerate (two-color) time-resolved Z-scan techniques, with femtosecond time resolution,have been implemented to measure the magnitude and dynamical processes of the optical nonlinearities of ZnSe. In the time-resolved Z-scan spectra a reversal of sign in the refractive-index change Deltan as a function of time delay was observed. A bound electronic contribution with a resolution limited response s,200 fs) gave rise to a positive Deltan at zero time delay, whereas a free-carrier contribution resulted in a negative Deltan at longer time delays. The free-carrier contribution to Deltan has two initial rapid relaxation components with time constants of a few picoseconds and a few tens of picoseconds, respectively. The longlived carriers also contributed to a slow relaxation component in Deltan on a nanosecond time scale.

20.
Angiology ; 44(8): 661-7, 1993 Aug.
Article in English | MEDLINE | ID: mdl-8342884

ABSTRACT

The authors report 2 cases of common carotid artery (CCA) occlusion and 4 cases of extracranial internal carotid artery (ICA) occlusion with forward Doppler ophthalmic artery flow. The compression test during Doppler study showed that the ophthalmic artery flow was reduced to zero when compressed contralateral to the CCA in 1 case of CCA occlusion and when compressed ipsilateral to the CCA in all 4 cases of ICA occlusion. The angiograms showed that in the 2 cases of CCA occlusion, 1 had the ophthalmic artery originating from the anterior communicating artery, and the other had subclavian steal syndrome with a reversed vertebral flow. In 3 of the 4 cases of ICA occlusion, the ophthalmic artery was found to originate from the ipsilateral middle meningeal artery. Their findings suggest that in cases of extracranial carotid artery occlusion, the forward ophthalmic artery flow is supplied from the contralateral CCA in cases of CCA occlusion and from the branches of the ipsilateral external carotid artery in cases of ICA occlusion, and the vertebrobasilar system plays a less important role.


Subject(s)
Carotid Stenosis/diagnostic imaging , Ophthalmic Artery/diagnostic imaging , Adult , Aged , Carotid Arteries/diagnostic imaging , Carotid Artery, External/diagnostic imaging , Carotid Stenosis/physiopathology , Female , Humans , Male , Middle Aged , Radiography , Regional Blood Flow , Rheology/instrumentation , Ultrasonography
SELECTION OF CITATIONS
SEARCH DETAIL
...