Acute myocardial ischemia enhances the vanilloid TRPV1 and serotonin 5-HT3 receptor-mediated Bezold-Jarisch reflex in rats.

The Bezold-Jarisch reflex is characterized by a sudden bradycardia associated with hypotension induced by the activation of the vanilloid TRPV1 and serotonin 5-HT(3) receptors. This reflex is associated with several health conditions, including myocardial infarction. The aim of the present study was to elucidate the influence of acute experimental myocardial ischemia on the reflex bradycardia induced by anandamide and phenylbiguanide, agonists of the TRPV1 and 5-HT(3) receptors, respectively.

Urethane, but not pentobarbitone, attenuates presynaptic receptor function in rats: a contribution to the choice of anaesthetic.

Background And Purpose: We examined whether cannabinoid CB(1) and histamine H(3) receptors resemble alpha(2)-adrenoceptors in that their presynaptically mediated cardiovascular effects are less marked in urethane- than in pentobarbitone-anaesthetized pithed rats.

Experimental Approach: Effects of the cannabinoid agonist CP-55,940 and the H(3) receptor agonist imetit on electrically induced tachycardic and vasopressor responses, respectively, was compared in pithed rats anaesthetized with urethane or pentobarbitone. The affinity of urethane for the three receptors was measured by radioligand binding studies in rat brain cortex membranes and its potency assessed in superfused mouse tissues preincubated with (3)H-noradrenaline.

Role of endocannabinoids in cardiovascular shock.

Endocannabinoids (e.g. anandamide, 2-arachidonoylglycerol or virodhamine) regulate the function of the cardiovascular system mainly in the following way: 1) by acting via CB(1) receptors, 2) by activation of CB(2) receptors, and 3) by modifying the function of vanilloid TRPV1, serotonin 5-HT(3) and alpha(7)-subunit-containing nicotinic acetylcholine receptors.