M₂, M₃, and M₄ muscarinic receptors are expressed in the guinea pig gallbladder

Abstract

Aim: 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 M₁, M₂, M₃, or M₄ 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 M₁–M₄ receptor subtypes. Results: M₂, M₃, and M₄ transcripts were detected in the following rank order: M₄ > M₂ > M₃. We were unable to demonstrate the expression of the M₁ receptor subtype in this tissue. Conclusions: Our results are in agreement with our previous binding and functional data.

Keywords::

• Muscarinic receptors
• guinea pig gallbladder
• RT-PCR

Acknowledgments

This work was funded by National Institutes of Health USA (FIRCA grants RO 3 TW00615, NS 25743 and NS 30454) and Marmara University Research Fund (Grant HEA-083/131200).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.