Regional haemodynamic effects of mu-, delta-, and kappa-opioid agonists microinjected into the hypothalamic paraventricular nuclei of conscious, unrestrained rats.
1. The cardiovascular effects of bilateral injection into the hypothalamic paraventricular nuclei of selective mu-, delta-, and kappa-opioid receptor agonists were investigated in conscious, unrestrained Wistar Kyoto rats, chronically instrumented with pulsed Doppler flow probes for measurement of regional haemodynamics. 2. The selective mu-agonist [D-Ala2,MePhe4,Gly5ol]enkephalin (DAMGO), injected bilaterally into the hypothalamic paraventricular nuclei (0.01-1.0 nmol), caused increases in blood pressure, tachycardias, vasoconstriction in renal and superior mesenteric vascular beds and substantial vasodilatation in the hindquarter vascular bed. 3. The administration of increasing doses (0.01-5.0 nmol) of the selective delta-agonist [D-Phe2,5]enkephalin (DPDPE) or the selective kappa-agonist, U50488H into the paraventricular nuclei (PVN) had no significant effect on blood pressure, heart rate, or regional haemodynamics. 4. Together, the present results are further evidence of a role for opioid peptides, especially acting at mu-receptors in the PVN, in the central regulation of the cardiovascular system, whereas a role for opioid peptides, acting at delta- and kappa-receptors in the PVN, seems less obvious from the present results.
Bachelard
H
H
Unité de Recherche sur l'Hypertension, CHUL, Université Laval, Ste-Foy, P.Q., Canada.
Pître
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D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000008:administration & dosage / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006614:Hindlimb / Q000098:blood supply / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D008845:Microinjections; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D017465:Receptors, Opioid, delta / Q000819:agonists*; D017473:Receptors, Opioid, kappa / Q000819:agonists*; D017450:Receptors, Opioid, mu / Q000819:agonists*; D012077:Renal Artery / Q000187:drug effects; D013610:Tachycardia / Q000139:chemically induced; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D000700:Analgesics; D000959:Antihypertensive Agents; D004745:Enkephalins; D011759:Pyrrolidines; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D020881:Enkephalin, D-Penicillamine (2,5)-