Neuroscience 2002 Abstract
| Presentation Number: | 738.8 |
|---|---|
| Abstract Title: | Δ<sup>9</sup>-THC PRETREATMENT CONCOMITANTLY PREVENTS BOTH 5-HTP-INDUCED 5-HT<sub>3</sub>-RECEPTOR MEDIATED VOMITING AND 5-HT<sub>2A</sub> RECEPTOR-MEDIATED HEAD-TWITCHING IN THE LEAST SHREW. |
| Authors: |
Darmani, N. A.*1
1Pharmacology, Kirksville College of Osteopathic Medicine, Kirksville, MO |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Neurotransmitters -- Cannabinoids |
| Session: |
738. Neurotransmitters: cannabinoids II Poster |
| Presentation Time: | Wednesday, November 6, 2002 4:00 PM-5:00 PM |
| Location: | Hall A2-B3 C-58 |
| Keywords: | Δ<sup>9</sup>-THC, vomiting, head-twitch, CB1 |
5-HT3 receptor agonists produce vomiting in the least shrew whereas 5-HT2A agonists induce the head-twitch response (HTR) in this species. Both behaviors were induced by the 5-HT precursor 5-hydroxytryptophan (5-HTP) in the absence and presence of a peripheral decarboxylase inhibitor, carbidopa (10 mg/kg). The aim of this study was to investigate: 1) whether Δ9-THC can prevent the induced behaviors, and 2) if the inhibitory effects are CB1 receptor-mediated. 5-HTP (0, 10, 50 and 100 mg/kg, i.p.) increased the frequencies of vomiting and HTR in shrews in a dose-dependent manner both in the absence and presence of carbidopa. However, in the presence of carbidopa the number of HTRs produced were 2-6.5 fold greater whereas the frequency of observed vomiting tended to be less. Two doses of 5-HTP (50 and 100 mg/kg) were chosen to determine the inhibitory action of Δ9-THC (1, 2.5, 5, 10 and 20 mg/kg) on the induced behaviors in the absence and presence of carbidopa. Lower doses of Δ9-THC were required to significantly prevent 5-HTP-induced emesis in the presence of carbodopa. However, similar doses of Δ9-THC were needed to reduce the HTR frequency in either condition. Relative to the induced emesis, the HTR appears to be more sensitive to the inhibitory action of Δ9-THC both in the absence and presence of carbidopa. The results suggest that Δ9-THC prevents 5-HTP-induced vomiting and HTR behaviors via inhibition of serotonin release. Both effects are cannabinoid CB1 receptor-mediated since the CB1 antagonist SR 141716A dose-dependently reversed the inhibitory effects of Δ9-THC on both behaviors.
Supported by NIH-NIDA Grant DA12605
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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