Dr. Kapusta et Va. Kenigs, Cardiovascular and renal responses produced by central orphanin FQ/nociceptin occur independent of renal nerves, AM J P-REG, 277(4), 1999, pp. R987-R995
Citations number
46
Categorie Soggetti
Physiology
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
The present study investigated the role of the renal nerves in mediating th
e cardiovascular and renal responses produced by the central administration
of the opioid-like peptide orphanin FQ/nociceptin (OFQ/N) in conscious Spr
ague-Dawley rats. In conscious rats, OFQ/N (10 mu g icy) produced a transie
nt bradycardia and hypotension (nadir 20 min). Although renal sympathetic n
erve activity (RSNA) initially remained unchanged, a delayed renal sympatho
inhibitory response occurred after recovery (30 min) of blood pressure. By
30 and 70 min postinjection, RSNA decreased to 75 and 66% of control, respe
ctively. Coinciding with the decrease in RSNA, central OFQ/N elicited a diu
resis and antinatriuresis that occurred independent of changes in renal hem
odynamics. In other studies, intracerebroventricular OFQ/N produced similar
cardiovascular and renal excretory responses in bilaterally renal-denervat
ed rats. Finally, in conscious sinoaortic deafferentiated rats, intracerebr
oventricular OFQ/N produced a rapid decrease in RSNA (55% of control, 10 mi
n; 38% of control, 20 min) that paralleled the onset of the hypotension and
bradycardia. These studies demonstrate that in conscious rats, intracerebr
oventricular OFQ/N produces a centrally mediated inhibition of RSNA which,
due to activation of baroreflex mechanisms, is temporally dissociated from
the hypotensive and bradycardia responses;As revealed in renal-denervated r
ats, the cardiovascular and renal excretory responses produced by central O
FQ/N occur by a pathway that is independent of intact renal nerves or chang
es in renal hemodynamics.