M2 muscarinic receptor agonists produce hypotension and bradycardia when injected into the nucleus tractus solitarii.
Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methyldioxolane (CD), but not those of a relatively selective M1 receptor agonist (McN-A343; 3 nmol/site), into the intermediate portion of nucleus tractus solitarii (NTS) of pentobarbital-anesthetized rats elicited a decrease in blood pressure (23-52 mm Hg) and heart rate (16-50 bpm). Previous microinjections of a selective competitive M2 receptor antagonist (AFDX-116; 0.8 nmol/site), but not those of a potent selective M1 receptor antagonist (pirenzepine; 2 nmol/site), into the NTS blocked the effects of CD. These results indicate that the muscarinic receptors in the intermediate portion of NTS are of M2 type.
Sundaram
K
K
Section of Neurosurgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103.
Murugaian
J
J
Watson
M
M
Sapru
H
H
D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D005971:Glutamates / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D010830:Physostigmine / Q000008:administration & dosage / Q000494:pharmacology*; D010890:Pirenzepine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000502:physiology; D012016:Reference Values
D005971:Glutamates; D000644:Quaternary Ammonium Compounds; D011976:Receptors, Muscarinic; D010890:Pirenzepine; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; D010830:Physostigmine; C048593:otenzepad