title: Role of Muscarinic Acetylcholine Receptor-2 in the Cerebellar Cortex in Cardiovascular Modulation in Anaesthetized Rats.
abstract: Our previous investigations have demonstrated that microinjection of acetylcholine (ACh) or muscarinic ACh receptor activation in the cerebellar cortex induces a systemic blood pressure depressor response. This study aimed to determine the role of muscarinic ACh receptor-2 (M2 receptor) in the cerebellar cortex in cardiovascular function regulation in rats. A nonselective muscarinic receptor agonist (oxotremorine M, OXO; 30 mM), a selective M2 receptor agonist (arecaidine but-2-ynyl ester tosylate, ABET; 3, 10, and 30 mM), 30 mM OXO mixed with a selective M2 receptor antagonist (methoctramine hydrate, MCT; 0.3, 1, and 3 mM), and normal saline (0.9 % NaCl) were separately microinjected (0.5 µl/5 s) into the cerebellar cortex (lobule VI) of anaesthetized rats. We measured the mean arterial pressure (MAP), maximum change in MAP, and reactive time (RT; the duration required for the blood pressure to return to basal levels), heart rate (HR) and the maximum change in HR during the RT in response to drug activation. The results demonstrated that ABET dose-dependently decreased MAP and HR, increased the maximum change in MAP and the maximum change in HR, and prolonged the RT. Furthermore, MCT dose-dependently blocked the OXO-mediated cardiovascular depressor response. This study provides the first evidence that M2 receptors in the cerebellar cortex are involved in cardiovascular regulation, the activation of which evokes significant depressor and bradycardic responses.
authors.affiliation: School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China. neurobiologyzhang@yahoo.com.
authors.forename: Changzheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China.
authors.forename: Tingzhe
authors.initials: T
authors.lastname: Sun
authors.affiliation: School of Life Sciences, Anhui Normal University, 1 East Beijing Road, Wuhu, 241000, Anhui, People's Republic of China.
authors.forename: Peiling
authors.initials: P
authors.lastname: Zhou
authors.affiliation: School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210046, Jiangsu, People's Republic of China. lfzhang@njnu.edu.cn.
authors.forename: Liefeng
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002525:Cerebellar Cortex / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008845:Microinjections; D018721:Muscarinic Agonists / Q000494:pharmacology*; D018727:Muscarinic Antagonists / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D043585:Receptor, Muscarinic M2 / Q000378:metabolism*
chemical_list: D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D043585:Receptor, Muscarinic M2
keywords: Blood pressure; Cerebellar cortex; Heart rate; Muscarinic acetylcholine receptor-2