Ohsawa M, Kamei J. Modification of kappa-opioid receptor agonist-induced antinociception by diabetes in the mouse brain and spinal cord.
J Pharmacol Sci 2005;
98:25-32. [PMID:
15879680 DOI:
10.1254/jphs.fp0040621]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The supraspinal and spinal antinociceptive effects of several kappa-opioid receptor agonists were examined in diabetic and non-diabetic mice using the tail-flick assay. The antinociception induced by intrathecal (i.t.), but not intracerebroventricular (i.c.v.), CI-977, a highly selective kappa(1)-opioid receptor agonist, in diabetic mice was less than that in non-diabetic mice. The antinociceptive effects of ICI-199,441 and R-84760, high potency kappa(1)-opioid receptor agonists, given i.c.v., but not i.t., were attenuated in diabetic mice compared to those in non-diabetic mice. On the other hand, the antinociceptive effects of the new kappa-opioid receptor agonist TRK-820, which has high affinity for kappa(2)- and/or kappa(3)-opioid receptors, injected both i.c.v. and i.t. in diabetic mice were markedly less than those in non-diabetic mice. These results indicate that the antinociceptive effects of those kappa-opioid receptor agonists in diabetic mice are altered in a region-specific manner in the central nervous system (CNS). The dysfunction of kappa-opioid receptor subtypes in diabetic mice may underlie this CNS region-specific variation in the effects of these kappa-opioid receptor agonists.
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