[Effect of xylazine on acetylcholine content of the hippocampal CA1 region in urethane anesthetized rats].
By using acetylcholine selective microelectrode technique, a biphasic effect of xylazine on acetylcholine content of the hippocampal CA1 region in urethane anesthetized rats was observed as evidenced by the fact that small doses of xylazine (2.0 and 6.0 mg.kg-1) significantly increased, while higher dose (10.0 mg.kg-1) decreased the acetylcholine content. Though idazoxan (0.6 mg.kg-1) significantly antagonized the effect of xylazine when used in combination, the acetylcholine content in the hippocampal CA1 region of urethane anesthetized rats was still much lower than that of the control group. In rats whose nucleus locus coeruleus was chemically lesioned, xylazine (2.0 and 6.0 mg.kg-1) significantly decreased the acetylcholine content, and idazoxan (0.6 mg.kg-1), which increased the acetylcholine content in the hippocampal CA1 region when used alone, completely antagonized the effect of xylazine. These results suggest that the biphasic effect of xylazine and the lower than normal acetylcholine content observed when idazoxan was used to antagonize xylazine induced changes in acetylcholine content of the hippocampal CA1 region in urethane anesthetized rats might be related to the effects of xylazine and idazoxan on the central noradrenergic neurotransmitter system.
Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing.
R G
RG
Ding
S J
SJ
Huang
J S
JS
Yang
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D004146:Dioxanes / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D019329:Idazoxan; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014991:Xylazine / Q000494:pharmacology*
D004146:Dioxanes; D014991:Xylazine; D000109:Acetylcholine; D019329:Idazoxan