Neuroscience 2002 Abstract
| Presentation Number: | 812.13 |
|---|---|
| Abstract Title: | EFFECT OF CANNABINOID RECEPTOR ACTIVATION ON LOCUS COERULEUS NEURONAL ACTIVITY. |
| Authors: |
Muntoni, A. L.*1
; Pillolla, G.2
; Pistis, M.2
; Gessa, G. L.2
1Inst Neurogenetics & Neuropharmacol, CNR, Cagliari, Italy 2B.B. Brodie Dept. of Neuroscience, University of Cagliari, Cagliari, Italy |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Addiction and Drugs of Abuse -- Basic Mechanisms |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Neurotransmitters<br />-- Cannabinoids |
| Session: |
812. Addiction and drugs of abuse: basic mechanisms II Poster |
| Presentation Time: | Wednesday, November 6, 2002 1:00 PM-2:00 PM |
| Location: | Hall A2-B3 AA-18 |
| Keywords: | cannabinoids, noradrenaline, electrophysiology |
Cannabis derivatives produce a variety of pharmacological responses including catalepsy, antinociception, hypothermia, cognitive and memory impairment, dependence, anxiolitic and anxiogenic reactions, modulation of vigilance state, cardiovascular effects. Because the locus coeruleus (LC), the main source of noradrenergic innervation in the CNS, has been implicated in the pharmacology underlying many of these actions, we sought to investigate the effect of CB1 receptor activation on the spontaneous discharge rate of LC noradrenergic neurons. Extracellular single-unit recordings from the LC were performed in chloral hydrate anaesthetized rats. Acute administration of the synthetic CB1 agonist WIN55,212-2 (0.062-1.0 mg/kg i.v.) produced a dose-dependent increase in the spontaneous firing rate of LC neurons (maximal stimulation 45±7% of baseline). Similarly, Δ9-THC (0.0625-1.0 mg/kg i.v.) elicited a slight, delayed activation of LC cells (maximal stimulation 32±5% of baseline). The stimulant response induced by either cannabinoid was reversed by the intravenous injection of 1.0 mg/kg SR141716A, a selective cannabinoid CB1 receptor antagonist. The effects of systemic administration of WIN55,212-2 and Δ9-THC were mimicked by intracerebroventricular application of the drugs. Further, experiments still in progress in our laboratory indicate that cannabinoids reduce the inhibition of LC from the nucleus prepositus hypoglossi, the major GABAergic afferent to the LC, suggesting that a reduction of GABA release from these terminals may be a mechanism by which CB1 ligands stimulate noradrenergic transmission.
Supported by CNR, Italy
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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