Neuroscience 2005 Abstract
| Presentation Number: | 291.1 |
|---|---|
| Abstract Title: | Estradiol enhances antinociceptive and motoric effects of THC. |
| Authors: |
Craft, R. M.*1
; Leitl, M. D.1
; Ulibarri, C. M.2
1Dept Psychol, Washington State Univ., Pullman, WA 2Dept VCAPP, Washington State Univ., Pullman, WA |
| Primary Theme and Topics |
Sensory and Motor Systems - Pain -- Psychophysics and behavior |
| Secondary Theme and Topics | Development<br />- Development of Sensory and Limbic Systems<br />-- Somatosensory system |
| Session: |
291. Nocieptive Processing: Modulation Poster |
| Presentation Time: | Sunday, November 13, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # CC15 |
| Keywords: | CANNABINOIDS, HORMONE, ANALGESIA, SEX DIFFERENCES |
We have previously shown that cannabinoid agonists, including delta-9-tetrahydrocannabinol (THC), are more potent and in some cases more efficacious in female than in male rats, in terms of their antinociceptive and motoric effects (Tseng & Craft, Eur J Pharmacol 430:41, 2001). In the present study, we manipulated gonadal steroid hormone state in adulthood, to determine to what extent activational effects of gonadal steroids are responsible for sex differences in sensitivity to the behavioral effects of THC. Adult Sprague-Dawley rats were gonadectomized; half of the females were implanted s.c. with estradiol (1-mm capsule/rat), and half of the males were implanted with testosterone (10-mm capsule/100 g body weight), and the rest of the rats were implanted with blank capsules of comparable length and number. Three weeks later, rats were injected with THC (5 mg/kg i.p.) or vehicle (1:1:18 emulphor:ethanol:saline) and tested for antinociception (tail withdrawal and paw pressure tests) and motor behaviors (horizontal locomotion and catalepsy). Estradiol significantly increased THC’s effects in females on the tail withdrawal, paw pressure and horizontal locomotion tests. These results suggest that estradiol in females is primarily responsible for sex differences in sensitivity to the behavioral effects of THC in rats. Because our previous studies indicate that sex differences in THC’s behavioral effects are likely due to sex differences in its metabolism (Tseng et al., Beh Brain Res 154:77, 2004), the next step will be to determine whether estradiol is enhancing THC’s effects in females by altering its metabolism.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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