Submitted to: Society for Neuroscience Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/1998
Publication Date: N/A
Technical Abstract: Because swine possess cannabinoid (CB) receptors in brain tissues, IN VIVO and IN VITRO experiments were conducted to determine the effects of CB agonists in swine on neuroendocrine and behavior parameters associated with stress and well-being. Intravenous infusion of WIN-55,212-2 (WIN,10 mg) elevated serum cortisol (p=0.02, n=3), whereas 20 mg of either methanandamide (MA) or anandamide failed to affect serum cortisol (p=0.43,n=5). To determine central sites of CB action, hypothalamic tissue was perifused and exposed to CB. Following a pretreatment period, tissues were exposed to either WIN or MA, and the release of CRF and beta-endorphin was measured. Both CB treatments increased hypothalamic beta-endorphin release (p=0.03, n=8; p=0.01, n=10) but neither CB agonist altered CRF release (p=0.44, n=8, p=0.74, n=12). In summary, IN VIVO administration of CB elevated serum cortisol levels, whereas IN VITRO exposure stimulated hypothalamic release of beta-endorphin but not CRF. The inability of CB to directly stimulate the IN VITRO release of hypothalamic CRF raises the possibility that the WIN-induced release of cortisol may involve either non-CRF induced stimulation of ACTH or an indirect stimulation of hypothalamic CRF. Alternatively, since changes in serum cortisol were always associated with anxiety-type behaviors, WIN may have provoked either a generalized anxiety or other central effects that would not be duplicated in hypothalamic perifusions.