ABSTRACT
Objective:To compare and explore the effects of needling acupoints at different nerve segmentson the oxytocin (OT) neurons in the paraventricular nucleus of hypothalamus (PVN) and the intragastric pressure, and discuss the possible mechanisms. Methods: Thirty-two healthy adult Sprague-Dawley (SD) rats were numbered and divided into 4 groups according to the random number table, a Zusanli (ST 36) group, a Neiguan (PC 6) group, a Weishu (BL 21) group and a control group, with 8 rats in each group. Except the control group, rats in the other three groups received acupuncture at the corresponding acupoints. To observe the differences in double-labeled OT neurons and c-fos neurons of the hypothalamic PVN and the intragastric pressure after acupuncture among the three groups of needling acupoints at different nerve segments. Results:Compared with the control group, the numbers of double-labeled cells in the PVN of the Zusanli (ST 36) group and the Neiguan (PC 6) group decreased significantly, while the intragastric pressure increased significantly (allP<0.05), and the inter-group differences were statistically significant (P<0.05). The intragastric pressure in the Weishu (BL 21) group decreased significantly, and the inter-group difference was statistically significant (P<0.05). Compared with the Weishu (BL 21) group, the numbers of OT/c-fos double-labeled cells in PVN of the Zusanli (ST 36) group and the Neiguan (PC 6) group decreased significantly, and the intragastric pressure increased significantly, the inter-group differences were statistically significant (allP<0.01). Conclusion:Acupoints at different nerve segments have different regulation effects on intragastric pressure. The difference may be related to the different nerve conduction pathways by acupoints at different nerve segments in regulating the intragastric pressure. The PVN may be one common integration center for the regulation of gastric function in the three acupoints [Zusanli (ST 36), Neiguan (PC 6) and Weishu (BL 21)] at different nerve segments.
ABSTRACT
Objective To evaluate the relationship between excitability of neurons in hypothalamic paraventricular nucleus (PVN) and central nervous regulatory mechanism of myocardial ischemia-reperfusion (I/R) injury in rats.Methods Clean-grade healthy adult male Sprague-Dawley rats,in which PVN catheters were successfully implanted,aged 6-8 weeks,weighing 260-300 g,were divided into 4 groups (n =6 each) using a random number table method:sham operation group (S group),myocardial I/R group (I/R group),γ-aminobutyric acid group (GABA group) and L-glutamic acid group (L-Glu group).Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery for 30 min followed by 120-min reperfusion.Normal saline 2.4 μl/h was infused for 50 min via the PVN catheter starting from 10 min before ischemia in S and I/R groups.GABA 30 μmol/L and L-glutamic acid 30 μmol/L were infused for 50 min via the PVN catheter at a rate of 2.4 μl/h starting from 10 min before ischemia in GABA and L-Glu groups.The heart rate (HR) and mean arterial pressure (MAP) were recorded at 10 min before ischemia (T0),beginning of ischemia (T1),30 min of ischemia (T2) and 120 min of reperfusion (T3).Rate-pressure product (RPP) was calculated.Blood samples were collected at T3 for determination of plasma cardiac troponin I (cTnI) concentrations by chemiluminescence assay.Rats were then sacrificed and myocardial specimens were obtained for measurement of myocardial infarct size (IS) and area at risk (AAS),and IS/AAR percentage was calculated.PVN tissues were taken to detect the expression of cfos by Western blot.Results No myocardial infarction was found in group S,and myocardial infarction was marked in the other three groups.Compared with group S,the plasma cTnI concentrations were significantly increased,and the expression of c-fos in PVN was up-regulated in I/R,GABA and L-Glu groups (P＜0.05),and MAP,HR and RPP were significantly decreased at T1-3 in I/R and GABA groups and at T3 in group L-Glu (P＜0.05).Compared with group I/R,IS and IS/AAR percentage were significantly decreased,the plasma cTnI concentrations were decreased,the expression of c-fos in PVN was down-regulated,and HR,MAP and RPP were decreased at T1,2 in group GABA,and IS and IS/AAR percentage were significantly increased,the plasma cTnI concentrations were increased,the expression of c-fos in PVN was up-regulated,and HR,MAP and RPP were increased at T1,2 in group L-Glu (P＜0.05).Conclusion Excitability of neurons in hypothalamic PVN is involved in central nervous regulatory mechanism of myocardial I/R injury in rats:decreased excitability can attenuate myocardial I/R injury and increased excitability aggravates myocardial I/R injury.
ABSTRACT
Objective@#To elucidate the association between large conductance calcium-activated potassium channels (BKCa) in the paraventricular hypothalamic nucleus (PVN) and sympathetic outflow in rats with chronic heart failure (CHF) .@*Methods@#Male Wistar rats (6-7 weeks old) were randomized to sham operated group and CHF group (coronary artery ligation) . Two weeks after operation, BKCa inhibitor Iberiotoxin (IBTX) was infused into PVN by osmotic minipumps, rats were divided into following groups: sham+aCSF, CHF+aCSF, sham+low dose IBTX (0.125 nmol/nl) , CHF+low dose IBTX, sham+moderate dose IBTX (1.25 nmol/nl) , CHF+moderate dose IBTX, sham+ high dose IBTX (12.5 nmol/nl) , and CHF+high dose IBTX (n=6 each) . Additional rats were grouped as follows: sham+vehicle, sham+KCNMB4 knockdown (by rAAV2-KCNMB4 shRNA virus injection in PVN) , CHF+vehicle, CHF+ KCNMB4 knockdown group (n=6 each) . The cardiac function was determined by echocardiography, left ventricular hemodynamics were measured invasively, renal sympathetic nerve activity (RSNA) was recorded at 6 weeks after coronary artery ligation or sham operation. The contents of norepinephrine (NE) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in plasma were determined by enzyme-linked immunosorbent assay. The protein and mRNA expression of KCNMB4 in PVN were measured by immunofluorescence staining, Western blot, and real-time PCR, mRNA expression of BKCa in PVN was detected by real-time PCR.@*Results@#Compared with the sham operation group, the cardiac function of the heart failure group was significantly reduced (P<0.05) , and the plasma NE and the serum NT-proBNP were significantly elevated (P<0.05) . The protein and mRNA expression of KCNMB4 in PVN were obviously down-regulated in CHF rats (P<0.05) . After perfusion of IBTX or KCNMB4 knockdown by microinjection of rAAV2-KCNMB4 shRNA virus,right ventricular weight/body weight and lung weight/body weight ratio as well as left ventricular end-diastolic diameter were increased and left ventricular ejection fraction was decreased (all P<0.05) , the sympathetic driving indexes was increased in sham rats, changes of these parameters further aggravated in CHF rats (P<0.05) . KCNMB4 knockdown further downregulated protein expression in PVN of CHF rats.@*Conclusion@#Downregulation and blunted function of BKCa in PVN may contribute to sympathoexcitation and deterioration of cardiac function in rats with chronic heart failure.
ABSTRACT
BACKGROUND:Previous studies concerning neuromechanism of acupuncture for regulating gastric function mainly focused on peripheral nerve, involving in central nervous system. In particular, there are few studies addressing higher central nervous system. OBJECTIVE:To explore the effects of acupuncture at Neiguan (PC6) and Zusanli (ST36) on gastric-related neurons in the hypothalamic paraventricular nucleus. METHODS:Using microelectrode extracellular recording technique, gastric related neurons in the paraventricular nucleus were found in gastric distension rats. Stimulation was conducted for 30 seconds by hand acupuncture at Neiguan and Zusanli. The effects of acupuncture on gastric-related neurons in the paraventricular nucleus were observed. RESULTS AND CONCLUSION:The discharge of 109 neurons in the hypothalamic paraventricular nucleus of 60 rats was recorded. A total of 56 gastric-related neurons of the 109 neurons were observed. The number of neurons response to acupunctures at Zusanli, Neiguan, Pishu (BL20) and Weishu (BL21) were respectively 44, 47, 29, and 33, with the reaction proportion of 78.57%, 83.47%, 51.79%and 58.93%. Results suggested that there exist gastric distension stimulation and acupuncture stimulations from neurons soma to visceral reaction in the hypothalamic paraventricular nucleus, which simultaneously participates in the regulation of acupuncture on the gastric function.
ABSTRACT
Objective To investigate the effect of methylprednisolone (MP) therapy on apoptosis of neurons in the paraventricular nucleus (PVN) after traumatic brain injury (TBI) in rats.Methods A total of 185 Wistar rats were divided into sham operation group (n =20),trauma control group (n =45),low-dose MP therapy group (n =50) and high-dose MP therapy group (n =70),according to the random number table.TBI models were induced by fluid percussion injury.TUNEL staining,immunohistochemistry and transmission electron microscope were used to detect PVN neuron number and apoptosis.Results Apoptotic neurons in the PVN were 0.7 ± 1.6,rare in sham operation group,whereas apoptotic neurons in trauma control group were firstly detected at 3 days and reached peak at 7 days (36.4 ± 18.8),with a slump of corticotropin-releasing hormone (CRH) for 208.0 ± 19.8.High-dose MP therapy markedly increased the neuron apoptosis (70.7±27.2),reduced CRH-positive cells (141.7 ±32.6),and increased short-term mortality (55％) when compared to trauma control group (all P ＜ 0.05).In contrast,low-dose MP greatly reduced PVN neuron apoptosis (17.6 ± 6.9),but increased CRH-positive cells (249.2 ±20.3) (P＜0.05) and decreased the short-term mortality (10％).Conclusions High-dose MP therapy increases neuronal apoptosis in PVN and short-term mortality after TBI.However,low-dose MP protects PVN neurons against TBI-induced apoptosis and reduces the mortality.
ABSTRACT
Arginine vasopressin (AVP) is a neuropeptide with vasoconstrictive, antidiuretic, cardiovascular regulative and hepatic glycogenolysis effects, that also affects other behaviors including modulating learning. A number of studies on AVP regulation have been conducted in various metabolic diseases (disorders). In this study, the immunoreactivities of AVP in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) and mRNA expressions in the hypothalamus were investigated by immunohistochemistry and quantitative real-time PCR (RT-qPCR) in stroke-prone spontaneously hypertensive rats at different ages (i.e., at postnatal months [PM] 1, 8, and 12). Blood glucose levels in the PM 8 group were higher than in the other groups. However, cresyl violet positive neurons were detected in the PVN and SON of all animals, and numbers of cresyl violet positive neurons were similar in all aged groups. In addition, AVP immunoreactivity was detected in the PVN and SON of all age groups, and AVP immunoreactivity and mRNA expression levels were found to be increased in proportion to age by immunohistochemistry and RT-qPCR. These results suggest that the diabetic condition is temporally generated after hypertension has developed. Furthermore, our findings suggest that increased AVP expressions in the hypothalamic PVN and SON are associated with hypertension by age.
Subject(s)
Aged , Animals , Humans , Arginine , Arginine Vasopressin , Benzoxazines , Blood Glucose , Glycogenolysis , Hypertension , Hypothalamus , Immunohistochemistry , Learning , Metabolic Diseases , Molybdenum , Neurons , Neuropeptides , Oxides , Paraventricular Hypothalamic Nucleus , Rats, Inbred SHR , Real-Time Polymerase Chain Reaction , RNA, Messenger , Supraoptic Nucleus , ViolaABSTRACT
Objective To observe the regulative effect of high dose of glucocorticoid (GC) on protein synthesis and mRNA transcription of corticotropin-releasing hormone (CRH) in paraventricular hypothalamic nucleus (PVN) so to ascertain whether there exists difference upon effect of GC either at high dose or at normal dose. Methods A total of 60 Wistar rats were divided into five groups, ie, blank control group, 10 -6 mol/L dexamethasone (DEX) group, 10 -9 mol/L DEX group, 9 g/L saline group and group that was treated with 10 -4 mol/L RU486 first and then with 10 -6 mol/L DEX. The drugs were given through femoral vein. CRH protein expression was measured by means of immunohistochemistry and laser confocal scanning microscophy (LCSM); CRH mRNA transcription level was investigated by in situ hybridization. Results There appeared positive CRH mRNA granules in cytoplasm of PVN after administration with 10 -6 mol/L DEX for 20 minutes but could be seen positive fluorescent granules of CRH protein 30 minutes later, which was reversed at an in advance blockage of GR, as was free in 10 -9 mol/L DEX group, 9 g/L saline group and blank control group. Conclusions High dose of GC can up regulate CRH gene expression in PVN and differs much from the traditional effect of GC at normal dose, as may be due to that high dose of GC exerts effects depending on membrane glucocorticoid receptor but normal dose of GC dose via iGR.
ABSTRACT
AIM: To investigate the role of the nucleus tractus solitarius (NTS) in the regulation of paraventricular nucleus (PVN) AVP-ergic neurons on gastric ischemia- reperfusion injury (GI-RI). METHODS: Male SD rats were used in experiments. The celiac artery were clamped for 30 min and reperfused 1 h by removal of the clamp to obtain the ischemia-reperfusion state. The mechanism was analysed with nucleus electrical stimulation, electrolytic lesion and nucleus microinjection technique. RESULTS: Microinjection of arginine-vasopressin (AVP) into PVN obviously attenuated the GI-RI and dose-dependent effects were observed ( r= -0.477, P
ABSTRACT
BACKGROUND: Using c-fos expression one of the immediate early gene, as a marker of altered neuronal response, we investigated the effect of superior cervical ganglion block (SCGB) exhibiting the same effect of SGB of human on the activity of several brain regions which are considered as located on autonomic neural pathway and neuroendocrine axis in rat. METHOD: The 48 Sprague-Dawley strain rats were divided into 4 groups, as saline/stress (control) group, SCGB/stress (tested) group, saline group, SCGB group. Superior cervical ganglion block was conducted in the SCGB/stress group and SCGB group while saline/stress and saline group were sham operated. After then restraint stress was imposed on the animals of SCGB/stress group and saline/stress group. And 2 hour after injection (saline, SCGB group) or restraint stress (saline/stress, SCGB/stress group), c-fos protein (Fos) was localized by immunocytochemistry. RESULTS: Much stronger Fos immunoreactivity was induced in the several brain region of control group rats compared to other three groups and the numbers of Fos positive cell count of tested group were significantly decreased in paraventricular hypothalamic nucleus (p<0.01), A5 (p<0.01), raphe pallidus (p<0.05), nucleus tractus solitaius (p<0.01) compared to control group. CONCLUSION: This study demonstrate that superior cervical ganglion block attenuates stress induced neuronal activities of paraventricular hypothalamic nucleus, A5, raphe pallidus, nucleus tractus solitarius.
Subject(s)
Animals , Humans , Rats , Axis, Cervical Vertebra , Brain , Cell Count , Genes, vif , Immunohistochemistry , Neural Pathways , Neurons , Paraventricular Hypothalamic Nucleus , Rats, Sprague-Dawley , Solitary Nucleus , Superior Cervical GanglionABSTRACT
AIM:To study the effect of intraventricular injection(icv) of histamine(HA) on corticotropin releasing hormone (CRH) neurons activity in paraventricular nucleus (PVN) of hypothalamus. METHOD: Fos ontogenic protein immunohistochemistry and double antigen immunohistochemistry method; semiquantitative reverse transcription-polymerase chain reaction(RT-PCR) method were used. RESULTS: After intraventricular injection of HA, (1) number of Fos immunnoreactive positive neurons in PVN increased significantly; (2) double labeling experiments showed that there were 31 78%?1 59% of Fos immunoreactive cells in PVN expressed CRH simultaneously; (3) the CRHmRNA level in PVN was increased in a dose-dependent manner. CONCLUSION: Central histamine activated CRH neurons in PVN of hypothalamus and increase the expression of CRH gene.
ABSTRACT
The origin of afferent connections to the hypothalamic paraventricular nucleus was studied in the rats with the method ot retrograde axonal transport of HRP.A small amount of HRP was delivered electrophretically into the hypothalamic paraventricular nucleus. The HRP labelled cells ware observed in the lateral septal nucleus, amygdaloid nucleus, hippocampus, subiculum,bed nucleus of the stria terminalis, -parafascicularic nucleus of the thalamus, anterior hypothalamic area, suprachiasmatica nucleus, supraoptic nucleus, circalaris nucleus, hypothalamic dorsomedial nucleus, hypothalamic ventromedial nucleus, posterior hypothalamic nucleus, arcuate nucleus, mamillaris nucleus, midbrain central gray, dorsal tegmental nucleus, lateral parabrac-hial nucleus, median raphe nucleus, locus coeruleus, solitary nucleus and lateral rati-cular nucleus