2014 Jun 18. pii: S0091-3057(14)00177-4. doi: 10.1016/j.pbb.2014.06.007. [Epub ahead of print]
Cyclic ovarian hormone modulation of supraspinal Δ9-tetrahydrocannabinol-induced antinociception andcannabinoid receptor binding in the female rat.
Abstract
Estrous cycle-related fluctuations in delta-9-tetrahydrocannabinol (THC)-induced antinociception have been observed in the rat. The aim of this study was to determine which major ovarian hormone modulates the antinociceptive effects of i.c.v. THC, and whether hormone modulation of THC’s behavioral effects could be due to changes in brain cannabinoid receptors (CBr). Vehicle (oil) or hormones (estradiol or progesterone, or both) were administered to female rats on Days 3 and 7 post-ovariectomy. On the morning or afternoon of Day 8 or Day 9, vehicle or THC (100μg) was administered i.c.v. Paw pressure, tail withdrawal, locomotor activity and catalepsy tests were conducted over a 3-hr period. Estradiol (with and without progesterone) enhanced THC-induced paw pressure antinociception only. Ovarian hormones time-dependently modulated CBr in brain structures that mediate antinociception and locomotor activity, but the changes observed in CBr did not parallel changes in behavior. However, the time course of CBr changes must be further elucidated to determine the functional relationship between receptor changes and antinociceptive sensitivity to THC.
Copyright © 2014. Published by Elsevier Inc.
Copyright © 2014. Published by Elsevier Inc.
KEYWORDS:
Antinociception; Cannabinoid; Female; Hormone; Locomotion; Radioligand Binding
- PMID:
- 24951841
- [PubMed – as supplied by publisher]
