Neuroscience 2000 Abstract
| Presentation Number: | 710.3 |
|---|---|
| Abstract Title: | Cannabinoid modulation of mesocortical dopaminergic system: electrophysiological study on prefrontal cortex neurons. |
| Authors: |
Pistis, M.*1
; Diana , M.2
; Melis, M.1
; Porcu, G.2
; Gessa, G. L.1
1Dept. of Neuroscience, Univ. of Cagliari, Cagliari, Italy 2Dept of Drug Sciences , Univ. of Sassari, Sassari, Italy |
| Primary Theme and Topics |
C. Excitable Membranes and Synaptic Transmission - 32. Inhibitory postsynaptic mechanisms |
| Secondary Theme and Topics | I. Neural Basis of Behavior<br />- 109. Learning and memory: pharmacology |
| Session: |
710. Inhibitory synaptic mechanisms: others Poster |
| Presentation Time: | Wednesday, November 8, 2000 3:00 PM-4:00 PM |
| Location: | Hall G-J |
| Keywords: | electrophysiology, cannabis, drugs of abuse, working memory |
The rat Prefrontal Cortex (PFC) receives a major inhibitory input from mesocortical dopaminergic system. Electrical stimulation of the Ventral Tegmental Area (VTA) produces a marked phasic inhibition of the electrical activity of most PFC neurons. Evidence suggests that cannabinoids may act as modulators of dopaminergic neuronal system. In the present study we utilized extracellular recordings in anaesthetized rats in order to determine whether the psychoactive constituent of marijuana Delta9-tetrahydrocannabinol (Delta9-THC), the synthetic cannabinoid agonist WIN55212,2 (WIN) and the antagonist SR141617A modulate the activity of neurons in the PFC and influence the inhibitory response induced by VTA stimulation. Electrical stimulation of VTA induced a marked inhibition, lasting 149.6±5.5 msec, of the spontaneous activity of PFC neurons. Acute administration of Delta9-THC (1mg/kg, i.v.) or WIN (0.5 mg/kg i.v.) reversed the electrically evoked inhibition of the majority of PFC neurons (73.3%, n=15). These effects were blocked by the CB1 receptor antagonist SR141617A (1 mg/kg i.v.). SR141617A alone produced a prolongation of inhibition in 55.6% of PFC cells studied (n=9). These results show that Delta9-THC and WIN countered the inhibition induced by VTA stimulation and hence may interfere with mesocortical neuronal transmission. On the other hand, SR141617-induced enhancement of PFC neuron inhibition suggests that endogenous cannabinoids may play a tonic role.
Supported by MURST 40%
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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