Primary structure of porcine cardiac muscarinic acetylcholine receptor deduced from the cDNA sequence

Abstract

The complete amino acid sequence of the porcine cardiac muscarinic acetylcholine receptor has been deduced by cloning and sequencing the cDNA. The tissue location of the RNA hybridizing with the cDNA suggests that this muscarinic receptor species represents the M2 subtype.

Tissue distribution of mRNAs encoding muscarinic acetylcholine receptor subtypes

“…It has previously been reported that rat pancreas contains mAChR III mRNA, but not mAChR I mRNA [6]. The presence of all four mAChR mRNAs in cerebrum agrees with previous observations as does the presence of mAChR II mRNA in heart [2,3,5,6,24]. The differential tissue distribution of the four mAChR mRNAs observed in the present investigation strengthens our previous conclusion that the mAChR heterogeneity in tissues with respect to antagonist binding is attributable to the presence of individual moIecuIarly distinct mAChR subtypes or various combinations of them [8].…”

Location of a region of the muscarinic acetylcholine receptor involved in selective effector coupling

“…In contrast, the exchange of this region between mAChR I and mAChR II does not significantly;affect the antagonist binding proper-ties of the two mAChR subtypes. The amino acid sequence of the putative cytoplasmic portion between the proposed transmembrane segments V and VI is divergent among the mAChR subtypes [2,12,[16][17][18]30,31].…”

“…The structures of chimaeric mAChRs are diagrammatically shown such that the putative transmembrane segments I-VII are aligned [2,16]; the fact that mAChR II differs from mAChR I in the lengths of the aminoterminal region preceding segment I (-2 amino acid residues), the region between segments V and VI (+ 24 residues) and the carboxy-terminal region following segment VII (-16 residues) is ignored. The compositions of the individual chimaeric mAChRs are as follows (the numbers in parentheses indicate amino acid numbers [2,16] Inward current is downward. The duration of ACh application is indicated by bars without taking into account the dead-space time in the perfusion system (-6 s).…”

“…The antagonist binding properties of individual mAChR subtypes expressed in Xenopus oocytes [2,3,12] show that mAChR I, mAChR II and mAChR III correspond most closely to the pharmacologically defined M1 (I), M2 cardiac (II) and M2 glandular (III) subtypes [13][14][15], respectively. This, together with the differential tissue distribution of the mRNAs encoding the individual mAChR species [2,[16][17][18][19], indicates that the mAChR heterogeneity in tissues with respect to antagonist binding is attributable to the presence of distinct mAChR gene products by themselves or in various combinations.…”

Muscarinic receptor modulation of glucose‐induced electrical activity in mouse pancreatic B‐cells

“…Thus, classical Ml-type muscarinic receptors have high affinity for pirenzepine, while classical M2-type muscarinic receptors have low affinity for this drug [14,15]. Recently, however, analysis of muscarinic receptor genes revealed the existence of four distinct receptor types [16][17][18].…”