ABSTRACT
OBJECTIVE To reveal the role of the basal forebrain(BF)GABAergic neurons in the regulation of isoflurane anesthesia and to elucidate the underlying neural pathways.METHODS The activity of BF GABAer-gic neurons was monitored during isoflurane anesthesia using a genetically encoded calcium indicator in Vgat-Cre mice of both sexes.The activity of BF GABAer-gic neurons was manipulated by chemogenetic and opto-genetic approaches.Sensitivity,induction time and emer-gence time of isoflurane anesthesia were estimated by righting reflex.The electroencephalogram(EEG)power and burst-suppression were monitored by EEG recording.The effects of activation of GABAergic BF-thalamic reticu-lar nucleus(TRN)pathway on isoflurane anesthesia were investigated with optogenetics.RESULTS The activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia,obviously decreased during the induction of anesthesia and gradually restored during the emergence from anesthesia.Activation of BF GABAergic neurons with chemogenetics and optogenetics promoted behavioral emergence from isoflurane anesthesia,with decreased sensitivity to isoflurane,delayed induction and accelerated emergence from isoflurane anesthesia.Optogenetic activation of BF GABAergic neurons prom-oted cortical activity during isoflurane anesthesia,with decreased EEG delta power and burst suppression ratio during 0.8%and 1.4%isoflurane anesthesia,respectively.Similar to the effects of activating BF GABAergic cell bod-ies,photostimulation of BF GABAergic terminals in the TRN also strongly promoted cortical activation and behav-ioral emergence from isoflurane anesthesia.CONCLU-SION The GABAergic neurons in the BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthe-sia via the BF-TRN pathway.
ABSTRACT
The basal forebrain is a heterogeneous structure at the base of the brain that participates in the regulation of sleep?wake, cognition, consciousness, and attention. Previous studies have suggested that these functions are mainly mediated by cholinergic neurons in the basal forebrain. With advances in research techniques, the understanding of basal forebrain cholinergic neurons, as well as GABAergic neurons and glutamatergic neurons, is deepened. The role of different neurons in the basal forebrain in the regulation of sleep?wake is summarized in this article. GABAergic neurons play a key role in promoting wakefulness, cholinergic neurons play an important role in sleep?wake homeostasis, and glutamatergic neurons provide excitation signals to other neurons.
ABSTRACT
The basal forebrain is a heterogeneous structure at the base of the brain that participates in the regulation of sleep-wake, cognition, consciousness, and attention. Previous studies have suggested that these functions are mainly mediated by cholinergic neurons in the basal forebrain. With advances in research techniques, the understanding of basal forebrain cholinergic neurons, as well as GABAergic neurons and glutamatergic neurons, is deepened. The role of different neurons in the basal forebrain in the regulation of sleep-wake is summarized in this article. GABAergic neurons play a key role in promoting wakefulness, cholinergic neurons play an important role in sleep-wake homeostasis, and glutamatergic neurons provide excitation signals to other neurons.
ABSTRACT
Objective To provide new experimental evidences associated with the mechanisms of inhaled anesthetics, the effects of sevoflurane on the electric activities of inhibitory interneurons in basal forebrain area (BF) were observed.Methods C57BL/6 mice, aged 2-3 weeks, were used and BF sections were cut for whole patch-clamp recording.Artificial cerebrospinal fluid containing sevoflurane was given and action potential, inhibitory postsynaptic potential were recorded.Results Sevoflurane could increase the frequency of firing rate of inhibitory interneurons in basal forebrain area (P<0.001), which could increase the frequency of action potential caused by depolarization current (P<0.05), and increase the frequency of spontaneous inhibitory postsynaptic currents of pyramidal neurons (P<0.05), while AP-depended miniature inhibitory postsynaptic currents were not significantly changed.Conclusion The basal forebrain inhibitory interneurons are involved in the anesthetic effect of sevoflurane.
ABSTRACT
The basal forebrain (BF) is known to participate in the control of motion, attention, learning and memory, and it also plays a key role in sleep-wake regulation. Although there is a strong heterogeneity among neurons in the BF, the main types are cholinergic, gamma-aminobutyric acid (GABAergic) and glutamatergic neurons. This review provided the research progress in the regulation of sleep-wakefulness behavior by the 3 neurons in the BF. The cholinergic neurons play roles in activation of cortex and promote phase transition between sleep and wakefulness. The cortical projecting GABAergic neurons, which accept the projections from the adjacent cholinergic and glutamatergic neurons, contribute to awakening and the maintenance of normal wakefulness. The GABAergic interneurons may promote sleepiness by inhibiting the wake-active neurons which excite the cortical neurons. The glutamatergic neurons regulate sleep and wakefulness by interacting with neighbor cholinergic and cortical projecting GABAergic neurons or through the direct projection to the cortex as well.
ABSTRACT
The present study was designed to elucidate the effects of rostral basal forebrain lesions on neuropeptide containing neurons in the cerebral cortex. Nine male Sprague-Dawley rats[250-300gm] received bilateral injections of ibotenic acid into the basal forebrain[A : +0.7mm, L : 2.3mm, D : 8.6mm] and additional five served as sham operated animals. Brains were removed at 8-14 days after lesioning and frozen coronal sections of 40 micrometer thickness were made. Immunohistochemical staining was performed against the somatostatin[SOM], neuropeptide Y[NPY], and vasoactive intestinal polypeptide[VIP]. No differences were observed in the number of the SOM-immunoreactive[SOM-ir] or NPY-ir neurons between the lesioned and the control groups. Density of the NPY-ir fibers also did not show any significant difference between the two groups. In contrast, the number of VIP-ir neurons in the frontal cortex was significantly reduced following the basal forebrain lesioning. These results suggest the functional relationship between the basal forebrain and the cortical VIP-ir neurons.
Subject(s)
Animals , Humans , Male , Rats , Brain , Cerebral Cortex , Ibotenic Acid , Immunohistochemistry , Neurons , Neuropeptide Y , Neuropeptides , Prosencephalon , Rats, Sprague-Dawley , Somatostatin , Vasoactive Intestinal PeptideABSTRACT
Objective To study the effect of ovarian estrogen on the expression of estrogen receptor beta (ER beta) of the basal forebrain of mice. Methods Ovariectomized (OVX) mice were used as animal model, and nickel ammonium sulfate intensified immunohistochemical SP technique was used to detect the changes of ER beta expression in the basal forebrain. Results The expression of ER beta in the basal forebrain of mice decreased dramatically, after OVX decreased to the lowest levels at 3 d after OVX, increased gradually, and recovered to normal level 20 d later. Conclusion Ovarain estrogen can regulate the expression of ER ? of the murine basal forebrain, indicating that estrogen, via ER ?, can regulate the nerous structure and function of the basal forebrain, which may be the mechanism of estrogen replacement therapy on Alzheimer′s brain.
ABSTRACT
In order to study the cause of mental deterioration and increase of plaques and tangles in the basal forebrain in Alzheimer's disease, we have used isolated neural cells from the nuclei of amygdala (A), the hippocampus(H), the nuclei of medial septum (S), and the basal nuclei of Meynert (M) of basal forebrain, and the retina (R) of newborn rats, to study the effect of cellular interactions on the growth activity of these cells. The growth activity was measured quantitatively using MTT colorimetric microassay method. The MTT results revealed that, after 3 days of culture, the most active cell growth were found in mixed cultures of A+H and H+R reaching up to 212％ and 270％ of their respective individual control cultures (p
ABSTRACT
Objective To investigate the distribution and chemical character of nestin immunoreactive cells in the human basal forebrain. Methods We explored systematically the distribution of nestin immunoreactive cells throughout the human basal forebrain by nestin 331B, 10C2, Rat401 antibody.Furthermore, we investigated the chemical identity of these nestin immunoreactive cells by using double\|labeling immunocytochemistry with NSE, ChAT, p75NGFR, GFAP antibody or using NADPH\|d histochemistry. Results The nestin immunoreactive cells were found in the septum, diagonal band of Broca, innominate substance,amygdala,basal nucleus of Meynert of adult human brain.These nestin immunoreactive cells haven big cell body,2\|3 processes.The nestin immunoreactive cells were labeled by NSE antibody.The large majority of those were single stained,and 28% were double labeled with ChAT positive neurons,15% with NGFR positive neurons,6% with NOS positive neurons.A few nestin immunoreactive cells shared similar morphology with that of astrocyte glia which existed in the spaces between the thin septa pellucida or the midline along the septum.It could not be labeled by GFAP antibody.Conclusion\ A new cluster of nestin immunoreactive neurons that were different from the ChAT,NGFR,NOS positive neurons existed in adult human basal forebrain.\;[