M2, M3, and M4 muscarinic receptors are expressed in the guinea pig gallbladder.
OBJECTIVE
The identity of muscarinic acetylcholine receptors (mAchR) involved in cholinergic-mediated contraction of the guinea pig gallbladder has been a matter of debate. Different groups have suggested the involvement of M(1), M(2), M(3), or M(4) receptor subtypes in the contraction of this tissue. The objective of this study was to identify the mAchR subtypes expressed in the guinea pig gallbladder by RT-PCR.


METHODS
Total RNA prepared from frozen guinea pig gallbladder tissue was amplified by using specific primers for the M(1)-M(4) receptor subtypes.


RESULTS
M(2), M(3), and M(4) transcripts were detected in the following rank order: M(4) > M(2) > M(3). We were unable to demonstrate the expression of the M(1) receptor subtype in this tissue.


CONCLUSIONS
Our results are in agreement with our previous binding and functional data.
Cabadak
Hulya
H
Department of Biophysics, Marmara University School of Medicine, Haydarpasa, Istanbul, Turkey.
Cuadra
Adolfo E
AE
El-Fakahany
Esam E
EE
Kan
Beki
B
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005704:Gallbladder / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D043643:Receptor, Muscarinic M1 / Q000235:genetics / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000235:genetics / Q000378:metabolism*; D043587:Receptor, Muscarinic M3 / Q000235:genetics / Q000378:metabolism*; D043588:Receptor, Muscarinic M4 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D043588:Receptor, Muscarinic M4