Effects of adenosine on sympathetic vasoconstriction in dog gracilis muscle.
The effects of intra-arterial infusions of adenosine (ADO) on sympathetic vasconstrictor responses were studied in the gracilis nerve-muscle preparation of the dog under constant flow conditions. Sympathetic nerves to the muscle were activated at a frequency of 1 Hz for 2 min during infusions of ADO, 2-chloroadenosine, nitroglycerine or hydralazine. ADO concentrations of 1, 10 and 50 microM decreased perfusion pressure by 19, 42 and 57 mm Hg, respectively, from a control (saline infusion) perfusion pressure of 110 mm Hg. Sympathetic vasoconstrictor responses were attenuated only at 50 microM ADO. Sympathetic responses during 1 and 10 microM ADO infusion were the same as during infusion of 10 and 100 microM nitroglycerine, which produced the same degree of vasodilation as 1 and 10 microM ADO, respectively. Except for greater vasodilator potency, 2-chloroadenosine infusions produced effects similar to ADO. Infusion of hydralize produced concentration-dependent decreases in control perfusion pressure and sympathetic vasoconstrictor responses. These results indicate that intra-arterial administration of ADO or one of its stable analogs (2-chloroadenosine) does not cause inhibition of sympathetic vasoconstrictor responses except at concentrations that cause nearly maximal vasodilation.
D015762:2-Chloroadenosine; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D006439:Hemodynamics / Q000187:drug effects; D006830:Hydralazine / Q000494:pharmacology; D008297:Male; D009132:Muscles / Q000098:blood supply; D005996:Nitroglycerin / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects*
D015762:2-Chloroadenosine; D006830:Hydralazine; D005996:Nitroglycerin; D000241:Adenosine