Neuroscience 2002 Abstract
| Presentation Number: | 810.15 |
|---|---|
| Abstract Title: | EFFECT OF Δ<sup>9</sup>-TETRAHYDROCANNABINOL (Δ<sup>9</sup>-THC) ON THE SINGLE-UNIT ACTIVITY OF SEROTONERGIC DORSAL RAPHE NEURONS IN FREELY MOVING CATS. |
| Authors: |
Jacobs, B. L.*1
; Fornal, C. A.1
1Prg Neurosci, Princeton Univ, Princeton, NJ |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Addiction and Drugs of Abuse -- Alcohol, barbituates, and benzodiazepines |
| Secondary Theme and Topics | Neurological and Psychiatric Conditions<br />- Addiction and Drugs of Abuse<br />-- Basic Mechanisms |
| Session: |
810. Addiction and drugs of abuse: alcohol, barbituates and benzodiazepines V Poster |
| Presentation Time: | Wednesday, November 6, 2002 3:00 PM-4:00 PM |
| Location: | Hall A2-B3 Z-102 |
| Keywords: | Serotonin, Cannabinoids, Marijuana, Arousal |
Brain serotonin has been implicated in the action of many psychoactive drugs. One agent of particular social and medical interest is Δ9-THC, the major active constituent in marijuana. Although a number of studies have characterized the effect of Δ9-THC on various neurochemical indices of serotonergic function, none has directly examined the effect of this compound on the electrophysiological activity of serotonergic neurons. To determine whether Δ9-THC alters serotonergic neuronal activity, we monitored the firing rate of serotonergic dorsal raphe neurons in behaving animals acutely treated with this agent. Serotonergic neurons were identified and recorded as described previously (Fornal et al., 2001). Systemic administration of Δ9-THC (5 mg/kg, i.p.) produced clear signs of sedation and impaired motor function, which are established characteristics of THC's action. These behavioral effects were evident within 15-30 min after injection and persisted for several hours. During periods when the cats were clearly awake, the activity of serotonergic neurons was decreased by 5-20% in response to Δ9-THC. During a synchronized sleep-like state induced by Δ9-THC, some cells displayed unusually long periods of inactivity (lasting up to 15 min), characteristic of the REM sleep state. These cells also exhibited an accelerated decline in activity during transitions from a desynchronized (waking) electroencephalogram to a synchronized (sleep-like) electroencephalogram. Overall, these findings suggest that behaviorally-active doses of Δ9-THC appear to be associated with a small, but significant, reduction in serotonin neurotransmission.
Supported by MIMH Grant MH-23433
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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