Cyclooxygenase inhibition does not impact the pressor response during static or dynamic mechanoreflex activation in healthy decerebrate rats.

We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Four minutes of both static and dynamic triceps surae muscle stretch increased interstitial PGE2 concentration above baseline values (static: ↑38%, p=0.01, dynamic: ↑56%, p<0.01, n=10). The four-minute protocol was required to collect enough microdialysate fluid for PGE2 detection. The finding that skeletal muscle stretch in vivo was capable of producing COX metabolites prompted the hypothesis that the COX inhibitor indomethacin (1 mg/kg, i.a.) would reduce the pressor and cardioaccelerator responses evoked during 30 seconds (the duration most commonly used in the rat mechanoreflex model) of static and dynamic rat triceps surae muscle stretch. We found that indomethacin had no effect (p>0.05, n=9) on the pressor or cardioaccelerator responses during 30 seconds of either static or dynamic stretch. We conclude that, despite skeletal muscle stretch-induced reductions in blood flow and the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin fiber muscle afferents stimulated during 30 seconds of static or dynamic mechanoreflex activation in healthy rats. PMID: 31241976 [PubMed - as supplied by publisher]
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research