Invited Symposium: Role of the Basal Forebrain Neurons in Cortical Activation and Behavioural State Regulation
Rainnie, DG (Dept. of Psychiatry, Harvard Medical School / Brockton VAMC, USA)
McCarley, RW (Dept. of Psychiatry, Harvard Medical School / Brockton VAMC, USA)
Greene, RW (Dept. of Psychiatry, Harvard Medical School / Brockton VAMC, USA)
The ventrolateral preoptic area (VLPO) contains a cluster of sleep-active neurons. Hence, the electrophysiological properties of a population of neurons that are potentially important in the regulation of sleep can be studied in vitro. In addition, the effects of the putative endogenous sleep factor adenosine (AD) can be investigated on these neurons. Stable whole cell patch-clamp recordings were obtained from 89 VLPO neurons in horizontal rat brain slices. Spontaneous synaptic activity of both epsp/c's and ipsp/c's is pronounced in many of these neurons. Most epsc/p's were DNQX (40 uM) sensitive. Most ipsc/p's were bicucculine (30 uM) sensitive. Some ipsc/p's were also DNQX sensitive suggesting they are driven by glutamatergic input. AD (20-100 uM) decreased the frequency of spontaneous ipsc/p's (17% to 100%)but had little effect on epsc/p frequency. In cells where AD decreased the frequency of spontaneous ipsc/p's, spontaneous firing rates increased or firing was initiated from silent cells under current clamp conditions. If increased activity in a population of VLPO neurons is involved in the regulation of sleep then one mechanism that AD may promote sleep is by decreasing a tonic inhibitory GABAA input on to VLPO neurons thus increasing their excitability.
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|Morairty, SR; Rainnie, DG; McCarley, RW; Greene, RW; (1998). Adenosine Mediated Disinhibition Of The Ventrolateral Preoptic Area. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium. Available at URL http://www.mcmaster.ca/inabis98/semba/morairty0461/index.html|
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