Endomorphin 1 and 2, endogenous mu-opioid agonists, decrease systemic arterial pressure in the rat.

M A Czapla; H C Champion; J E Zadina; A J Kastin; L Hackler; L J Ge; P J Kadowitz

doi:10.1016/s0024-3205(98)00048-4

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Endomorphin 1 and 2, endogenous mu-opioid agonists, decrease systemic arterial pressure in the rat.

M A Czapla·H C Champion·J E Zadina·A J Kastin·L Hackler·L J Ge·P J Kadowitz

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Abstract

The endogenous opioid peptides, endomorphin 1 and 2, are newly isolated, potent, and selective mu-opioid receptor agonists. In the present study, responses to endomorphin 1 and 2 were investigated in the systemic vascular bed of the rat. Endomorphin 1 and 2 induced dose-related decreases in systemic arterial pressure when injected in doses of 1-30 nmol/kg i.v. In terms of relative vasodepressor activity, endomorphin 1 and 2 were approximately equipotent with each other and with the ORL1 ligand, nociceptin (orphanin FQ), and were about 10-fold more potent than met-enkephalin in decreasing systemic arterial pressure. Vasodepressor responses to endomorphin 1 and 2 and met-enkephalin, but not to nociceptin, were inhibited by the opioid receptor antagonist, naloxone. These results demonstrate that endomorphin 1 and 2 produce significant naloxone-sensitive decreases in systemic arterial pressure.

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Analgesics, Opioid Animals Blood Pressure Enkephalin, Methionine Female Male Oligopeptides Opioid Peptides Rats Rats, Sprague-Dawley Receptors, Opioid, mu Vasoconstrictor Agents Nociceptin Journal Article

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M A Czapla, H C Champion, J E Zadina, A J Kastin, L Hackler, L J Ge, P J Kadowitz. 1998. Endomorphin 1 and 2, endogenous mu-opioid agonists, decrease systemic arterial pressure in the rat.. https://doi.org/10.1016/s0024-3205(98)00048-4

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