Ge X Q, Hu G, Yao B, Xu P C, Bian C F
Department of Pharmacology, Xuzhou Medical College, China.
Zhongguo Yao Li Xue Bao. 1995 Sep;16(5):408-11.
To study the relationship between muscarinic receptor (M-R) subtypes and cyclic nucleotides in pons-medulla oblongata (MeOb).
The contents of cGMP and cAMP in Sprague-Dawley rat pons-MeOb, cerebellum and cerebral cortex were assayed by radioimmunoassay and competitive protein-binding assay, respectively, after ip injections of drugs. Control rats were given ip normal saline.
M1-R agonist pilocarpine (6, 15 mg kg-1, ip) increased the content of cGMP in the pons-MeOb and cerebral cortex, but did not bring about any noticeable change in the cAMP content. The increase of cGMP was antagonized by ip pirenzepine or scopolamine. On the other hand, ip M2-R agonist 6 beta-acetoxy nortropane (6 beta-AN) 25 micrograms kg-1 reduced not only cAMP contents in the pons-MeOb and cerebellum but also cGMP contents in the pons-MeOb and cerebral cortex, while 6 beta-AN 12 micrograms kg-1 only lowered cAMP content. The decreases of cGMP and cAMP induced by 6 beta-AN were antagonized by ip AF-DX 116 or atropine, respectively.
Stimulation of M1-R causes the increase of cGMP and that of M2-R induces the decreases of both cGMP and cAMP in the pons-MeOb.
研究脑桥-延髓中毒蕈碱受体（M-R）亚型与环核苷酸之间的关系。
给Sprague-Dawley大鼠腹腔注射药物后，分别采用放射免疫分析法和竞争性蛋白结合分析法测定其脑桥-延髓、小脑和大脑皮质中cGMP和cAMP的含量。对照组大鼠腹腔注射生理盐水。
M1-R激动剂毛果芸香碱（6、15mg/kg，腹腔注射）可增加脑桥-延髓和大脑皮质中cGMP的含量，但对cAMP含量无明显影响。腹腔注射哌仑西平或东莨菪碱可拮抗cGMP的增加。另一方面，腹腔注射M2-R激动剂6β-乙酰氧基去甲托品（6β-AN）25μg/kg不仅可降低脑桥-延髓和小脑中cAMP的含量，还可降低脑桥-延髓和大脑皮质中cGMP的含量，而6β-AN 12μg/kg仅降低cAMP含量。腹腔注射AF-DX 116或阿托品可分别拮抗6β-AN诱导的cGMP和cAMP的降低。
刺激M1-R可导致脑桥-延髓中cGMP增加，刺激M2-R可导致脑桥-延髓中cGMP和cAMP均降低。
