Journal article

Publication year: 2022

Journal: European Journal of Pharmacology

Volume number: 933

ISSN: 0014-2999

eISSN: 1879-0712

DOI Link: https://doi.org/10.1016/j.ejphar.2022.175264

Publisher: Elsevier

Abstract: 
Proteinases released e.g. during inflammatory or allergic responses affect gastrointestinal functions via proteinase-activated receptors such as PAR1 and PAR2. As the gastrointestinal tract exerts pronounced gradients along its longitudinal axis, the present study focuses on the effect of PAR1 and PAR2 agonists on electrogenic ion transport (measured as short-circuit current; I-sc), tissue conductance (G(t)) and contractility of the longitudinal muscle layer of rats. In Ussing chamber experiments, the PAR1 agonist TFLLR-NH2, which mimics the tethered ligand liberated after cleavage of the receptor, evoked only a modest increase in I-sc (< 0.5 mu Eqmiddoth(-1)middotcm(-2)) in small intestine, but a strong increase (3-4 mu Eqmiddoth(-1)middotcm(-2)) in colon. Pretreatment with tetrodotoxin reduced the response of the colonic segments to the level of the small intestine. Thrombin, the natural activator of PAR1, was much less effective suggesting biased activation by this peptidase. A similar gradient along the longitudinal axis of the intestine was observed with trypsin, the endogenous activator of PAR2. Divergent actions of PAR1 activation by enzymatic cleavage or a mimetic peptide were also observed when recording isometric contractions of longitudinal muscle. For example, in the jejunum TFLLR-NH2 concentration-dependently induced a contractile response, whereas thrombin showed only inconsistent effects. The PAR2 activator AC264613 induced a concentration-dependent decrease in muscle tone combined with an inhibition of phasic spontaneous contractions. PCR experiments and immunohistochemical stainings confirmed the expression of PAR1 and PAR2. The data implies that PAR1 and PAR2 functions vary depending on the intestinal segment.

Harvard Citation style: Mirakhur, M. and Diener, M. (2022) Proteinase-activated receptors regulate intestinal functions in a segment-dependent manner in rats, European Journal of Pharmacology, 933, Article 175264. https://doi.org/10.1016/j.ejphar.2022.175264

APA Citation style: Mirakhur, M., & Diener, M. (2022). Proteinase-activated receptors regulate intestinal functions in a segment-dependent manner in rats. European Journal of Pharmacology. 933, Article 175264. https://doi.org/10.1016/j.ejphar.2022.175264