Endokinin A/B stimulates rat gastric motility through myogenic NK1 receptors located in fundus.

Endokinin A/B stimulates rat gastric motility through myogenic NK1 receptors located in fundus. Can J Physiol Pharmacol. 2020 May 04;: Authors: Zhang J, Ma C, Wang R, He C, Li H, Dong S Abstract Endokinin A/B (EKA/B), the common C-terminal decapeptide in endokinins A and B, is a preferred ligand of NK1 receptor and regulates pain and itch. The study focused on the effects of EKA/B on rat gastric motility in vivo and in vitro. Gastric emptying was measured to evaluate gastric motility in vivo. Intragastric pressure and the contraction of gastric muscle strips were measured to evaluate gastric motility in vitro. Moreover, various neural blocking agents and neurokinin receptor antagonists were applied to explore the mechanisms. TAC4 and TACR1 mRNA were expressed throughout rat stomach. EKA/B promoted gastric emptying by intraperitoneal injection in vivo. Correspondingly, EKA/B also increased intragastric pressure in vitro. Additionally, EKA/B contracted the gastric muscle strips from the fundus but not from the corpus or antrum. Further studies revealed that the contraction induced by EKA/B on muscle strips from fundus could be significantly reduced by NK1 receptor antagonist SR140333, but not NK2 receptor antagonist, NK3 receptor antagonist or the neural blocking agents used. Our results suggested that EKA/B might stimulate gastric motility mainly through the direct activation of myogenic NK1 receptors located in the fundus. PM...
Source: Canadian Journal of Physiology and Pharmacology - Category: Drugs & Pharmacology Authors: Tags: Can J Physiol Pharmacol Source Type: research