title: Is the M1-muscarinic receptor a candidate gene for hypertension in the spontaneously hypertensive rat?
abstract: 1. Central nervous system muscarinic receptors have been implicated in genetic models of hypertension as well as in stress adaptive cardiovascular responses. To determine if the sequence of the M1-muscarinic receptor is pathogenetic for hypertension, we analysed the differences between SHRLJ (spontaneously hypertensive rats) and WKYLJ (Wistar-Kyoto) rats in the sequence of the M1-receptor gene. 2. Specific primer sets were synthesized so as to cover the gene in 10 fragments (158-344 base pairs) with overlaps. Analysis was conducted by both polymerase chain reaction (PCR)-acrylamide and by single-stranded conformation polymorphism (SSCP). 3. No polymorphic locus was found by non-denaturing PCR-acrylamide nor by denaturing SSCP. Slight intrastrain variations in fragment 2 of the parental strains were examined by direct sequencing; however, no difference in sequence was found between SHRLJ and WKYLJ. To identify the chromosomal location and possible linkage with a polymorphic locus, rat/mouse somatic hybrid cell lines were examined. The rat M1-muscarinic receptor was assigned to chromosome 1. 4. Based on analysis of the coding sequence of the gene, our data do not support the hypothesis that the M1-muscarinic receptor is a candidate gene for hypertension. We conclude that, pending analyses of the promoter and regulatory regions of the gene, differences in the M1-muscarinic receptor in SHR either in receptor expression or in physiological response must be due to altered intracellular signalling or extracellular transynaptic events, but not due to a mutation of the gene sequence.
authors.affiliation: Department of Pharmacology, University of California at San Diego, La Jolla, USA.
authors.forename: C P
authors.initials: CP
authors.lastname: Klett
authors.forename: M P
authors.initials: MP
authors.lastname: Printz
mesh_terms: D000818:Animals; D004247:DNA / Q000032:analysis; D006973:Hypertension / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011976:Receptors, Muscarinic / Q000235:genetics*
chemical_list: D011976:Receptors, Muscarinic; D004247:DNA