Neuroscience 2003 Abstract
| Presentation Number: | 111.1 |
|---|---|
| Abstract Title: | Previous exposure to δ9-THC does not promote the pursuit of amphetamine. |
| Authors: |
Vezina, P.*1
; Austin, J. D.1
; Lorrain, D. S.3
; Beeler, J. A.2
; Tang, W.2
1Dept. Psychiatry, Univ. Chicago, Chicago, IL 2Ben May Inst. Cancer Res, Univ. Chicago, Chicago, IL 3CA, 5841 S. Maryland Ave, MC 3077, 60637, |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Addiction and Drugs of Abuse -- Basic mechanisms |
| Session: |
111. Addiction and Drugs of Abuse: Basic Mechanisms I Poster |
| Presentation Time: | Saturday, November 8, 2003 1:00 PM-2:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # VV49 |
| Keywords: | gateway, marijuana, self-administration, sensitization |
Rats previously exposed to amphetamine (AMPH) show enhanced locomotor and nucleus accumbens (NAcc) dopamine (DA) responding to the drug as well as enhanced self-administration of AMPH and cocaine. The present experiments assessed the effects of pre-exposing rats to Δ9-THC. Rats in different groups were given five pre-exposure injections of saline or one of five doses of Δ9-THC (0.4, 0.75, 1.5, 3.0, 6.0 mg/kg, IP), one injection every third day, and tested two to three weeks later. Previous exposure to all but the lowest dose of Δ9-THC enhanced the locomotor response to AMPH (0.75 mg/kg, IP) but all failed to enhance NAcc DA overflow in response to AMPH. Previous exposure to 3.0 mg/kg (IP, the most effective Δ9-THC dose above) also enhanced forskolin-evoked adenylyl cyclase activity in the NAcc and rats’ locomotor response to the direct DA receptor agonist apomorphine (1.0 mg/kg, SC), suggesting that previous exposure to Δ9-THC enhances locomotor responding to AMPH by up-regulating postsynaptic DA receptor signaling pathways in the NAcc. Finally, rats pre-exposed to 3.0 mg/kg (IP) Δ9-THC failed to show enhanced self-administration of AMPH (200 µg/kg/infusion, IV). Thus, unlike AMPH, previous exposure to Δ9-THC does not enhance the subsequent NAcc DA response to AMPH or promote the self-administration of this psychomotor stimulant drug. Although Δ9-THC pre-exposure leads to alterations in postsynaptic DA receptor signaling in the NAcc and these can impact the generation of locomotion, these neuroadaptations do not appear to be linked to the expression of enhanced self-administration behaviors. Rather, enhanced drug taking may depend on sensitized midbrain DA neuron reactivity.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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