title: Increased drinking in mutant mice with truncated M5 muscarinic receptor genes.
abstract: The rarest and least understood of the muscarinic receptors is the M5 subtype. Recombinant methods were used to create mutant mice with a deletion in the third intracellular loop of the M5 receptor gene. Salivation induced by the nonselective muscarinic agonist pilocarpine (1 mg/kg s.c.) was reduced in homozygous mutants from 15 to 60 min after injection as compared with wild-type mice. After 18-h food and water deprivation, drinking was increased in homozygous mutants, but feeding was not increased. The mutant and wild-type mice had similar responses in tests of open-field exploration, seizures induced by pilocarpine (300 mg/kg) or hypothermia induced by pilocarpine (1-3 mg/kg). These results indicate that M5 muscarinic receptors are important for fluid intake and suggest that M5 receptors are involved in slow secretory processes.
authors.affiliation: Department of Psychology, University of Toronto, Toronto, Ontario, Canada M5S 3G3.
authors.forename: Junichi
authors.initials: J
authors.lastname: Takeuchi
authors.forename: James
authors.initials: J
authors.lastname: Fulton
authors.forename: Zheng-ping
authors.initials: ZP
authors.lastname: Jia
authors.forename: Wanda
authors.initials: W
authors.lastname: Abramov-Newerly
authors.forename: Laure
authors.initials: L
authors.lastname: Jamot
authors.forename: Manu
authors.initials: M
authors.lastname: Sud
authors.forename: David
authors.initials: D
authors.lastname: Coward
authors.forename: Martin
authors.initials: M
authors.lastname: Ralph
authors.forename: John
authors.initials: J
authors.lastname: Roder
authors.forename: John
authors.initials: J
authors.lastname: Yeomans
mesh_terms: D000818:Animals; D004326:Drinking / Q000235:genetics*; D017353:Gene Deletion; D005838:Genotype; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D051381:Rats; D043642:Receptor, Muscarinic M5; D011976:Receptors, Muscarinic / Q000172:deficiency* / Q000235:genetics*
chemical_list: D043642:Receptor, Muscarinic M5; D011976:Receptors, Muscarinic