Neuroscience 2005 Abstract
| Presentation Number: | 485.13 |
|---|---|
| Abstract Title: | Behavioral and molecular evidence for long-lasting effects of perinatal cannabinoid exposure on the limbic opioid system. |
| Authors: |
Spano, S. M.*1
; Ellgren, M.1
; Hurd, Y. L.1
1Dept of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden |
| Primary Theme and Topics |
Development - Development of Sensory and Limbic Systems -- Limbic system |
| Secondary Theme and Topics | Cognition and Behavior<br />- Animal Cognition and Behavior<br />-- Stress and hormones |
| Session: |
485. Limbic System Development: Stress, Mood, and Behavior Poster |
| Presentation Time: | Monday, November 14, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # C48 |
| Keywords: | ABUSE, CANNABINOIDS, OPIOID, RELAPSE |
Functional cannabinoid-opioid interactions have been demonstrated in reward and relapse. Here we studied the effect of prenatal exposure to Δ9-tetrahydrocannabinol (THC) on the vulnerability for heroin reinforcement in adulthood. Pregnant Long Evans rats were exposed daily to THC (0.15 mg/kg iv) from gestational day 5 to post-natal day 2; adult males offspring were then trained to self-administer heroin (30 µg/kg/infusion). After stable self-administration was acquired, we determined the between-session dose-response (7.5-100 µg/kg/inf) curve, the consequence of exposure to a mild stress (1-day food deprivation) on heroin intake and the effect of different non-contingent, non-reinforced drug primings on heroin-seeking reinstatement following extinction. The results indicate that both groups had similar rates of responding during acquisition. However, THC-exposed rats exhibited a higher rate of responding to lower (7.5-15 µg/kg/inf) heroin doses compared to vehicle-exposed animals, while both groups responded similarly to higher (60-100 µg/kg/inf) doses. Moreover, THC-, but not vehicle-exposed rats, displayed an increased level of responding following mild stress. Priming injection of heroin (0.25 mg/kg sc) reinstated heroin-seeking behavior in both groups, an effect completely prevented by pretreatment with the cannabinoid receptor antagonist Rimonabant (3 mg/kg ip). Finally, mRNA levels of proenkephalin (PENK) and prodynorphin (PDYN) were analyzed in several brain nuclei of the adult offspring. PENK mRNA level was significantly increased in the ventral, but not dorsal, striatum as well as in the amygdala (central and medial nucleus) of THC-exposed animals, whereas the expression of PDYN was not altered in these regions by the prenatal THC exposure. This study demonstrates that prenatal exposure to THC alters heroin-intake and heroin-seeking in the adult offspring, inducing long-lasting specific opioid molecular alterations in limbic brain areas relevant to drug reward and stress response.
Supported by Supported by NIH DA12030
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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