Nociceptin/orphanin FQ modulates the cardiovascular, but not renal, responses to stress in spontaneously hypertensive rats.
1. The central administration of the endogenous opioid-like peptide nociceptin/orphanin FQ (N/OFQ) produces marked cardiovascular depressor and renal sympathoinhibitory responses in conscious animals. These findings are evidence that central N/OFQ may modulate the cardiovascular and renal responses to acute environmental stress. 2. The changes in cardiovascular and renal function produced by intracerebroventricular (i.c.v.) N/OFQ were measured in conscious spontaneously hypertensive rats (SHR) under basal conditions and during the acute environmental stimulus of air jet stress. 3. In SHR, central N/OFQ produced profound hypotensive, bradycardic, renal sympathoinhibitory (delayed) and water-diuretic effects by a pathway that does not involve activation of central alpha2-adrenoceptors or classical opioid receptors. 4. Intracerebroventricular injection of N/OFQ prevented the pressor response and blunted the tachycardia to air jet stress. A similar renal sympathoexcitatory and antinatriuretic response was observed in conscious SHR during air stress, before and after i.c.v. N/OFQ. 5. These findings are evidence that, in conscious SHR, i.c.v. N/OFQ selectively inhibited the neural responses to air jet stress by attenuating sympathetic outflow to the heart and, potentially, vasculature, but not to the kidneys. Central endogenous N/OFQ systems may be activated and contribute to regional changes in sympathetic outflow during acute stress.
Kapusta
Daniel R
DR
Department of Pharmacology and Experimental Therapeutics and the Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA. dkapus@lsuhsc.edu
Dayan
Lisa A
LA
Kenigs
Velga A
VA
D000320:Adrenergic Fibers / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002319:Cardiovascular System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007276:Injections, Intraventricular; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D018847:Opioid Peptides / Q000008:administration & dosage* / Q000502:physiology; D051381:Rats; D011918:Rats, Inbred SHR; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology; D013312:Stress, Physiological / Q000503:physiopathology / Q000517:prevention & control*; D013610:Tachycardia / Q000503:physiopathology / Q000517:prevention & control; D014665:Vasodilator Agents / Q000008:administration & dosage*; D000097629:Nociceptin
D018847:Opioid Peptides; D018341:Receptors, Adrenergic, alpha-2; D014665:Vasodilator Agents; D000097629:Nociceptin