Role of muscarinic receptors in renal response to acetylcholine.
Renal arterial infusion of acetylcholine (ACh) (40 micrograms/min) in control dogs produced an ipsilateral increase in renal plasma flow (RPF) and in sodium excretion (UNaV) without a change in glomerular filtration rate (GFR). The increase in RPF and UNaV was maintained during the infusion of ACh. In indomethacin (Indo)-treated dogs (5 mg/kg) ACh produced a transient rise in RPF and UNaV, followed by a progressive decline in RPF and UNaV. The profound renal vasoconstriction was accompanied by a decline in GFR. To determine the role of the muscarinic receptor in the renal vasodilation and in vasoconstriction produced by ACh in Indo-treated dogs, atropine at 6, 60, and 600 micrograms/min was infused into the renal artery before and during the infusion of ACh. In Indo-treated dogs, all dosages of atropine prevented renal vasoconstriction by ACh. Renal arterial infusion of atropine at 600 micrograms/min completely inhibited the renal vasodilation produced by ACh. Atropine infused at 60 micrograms/min partially inhibited, whereas 6 micrograms/min atropine failed to inhibit, the renal vasodilation produced by ACh. Our data suggest that the renal vasodilator and vasoconstrictor effects of ACh in Indo-treated dogs are mediated by two separate types of muscarinic receptors.
Yun
J C
JC
Department of Physiology and Biophysics, Howard University, Washington, District of Columbia 20059.
Oriji
G
G
Gill
J R
JR
Coleman
B R
BR
Peters
J
J
Keiser
H
H
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects*; D011976:Receptors, Muscarinic / Q000502:physiology*; D012079:Renal Circulation / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects
D011976:Receptors, Muscarinic; D001285:Atropine; D000109:Acetylcholine; D007213:Indomethacin