Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1984 Sep;83(1):187-93.
doi: 10.1111/j.1476-5381.1984.tb10134.x.

Potassium induces relaxation and hyperpolarization of circular muscles but contraction of longitudinal muscles of pig duodenum

I Kimura, M Kimura, M Kimura

Potassium induces relaxation and hyperpolarization of circular muscles but contraction of longitudinal muscles of pig duodenum

I Kimura et al. Br J Pharmacol. 1984 Sep.

Abstract

The mechanisms by which K+ relaxes circular muscles of pig duodenum were investigated, and compared with the response of the longitudinal muscles to K+. Circular muscles were concentration-dependently relaxed by 8.3-23.6 mM K+, but contracted by 47.2-143.4 mM K+. Longitudinal muscles were contracted by 11.8-94.4 mM K+. The relaxation of circular muscles was correlated with hyperpolarization (4 mV), but evoked Ca2+ spikes were not suppressed. Neither ouabain (0.14 microM) nor phentolamine (10 microM) blocked the relaxation, but tetrodotoxin (TTX, 0.63 microM) blocked both the relaxation and hyperpolarization. Mesaconitine (0.16 microM) increased the relaxation. Inhibitory junction potentials and concomitant relaxations were also blocked by TTX. The results suggest that K+-induced relaxation is caused by the release of a non-adrenergic inhibitory transmitter.

PubMed Disclaimer

References

    1. J Physiol. 1968 May;196(1):87-100 - PubMed
    1. Proc Soc Exp Biol Med. 1972 Jul;140(3):820-4 - PubMed
    1. Am J Physiol. 1974 Nov;227(5):1206-11 - PubMed
    1. Pflugers Arch. 1975 Oct 28;360(2):109-19 - PubMed
    1. Life Sci. 1975 May 15;16(10):1489-97 - PubMed