title: Cerebrovascular effects of ammonia in vitro.
abstract: The effect of ammonia (ammonium salts) upon human and rabbit cerebral arteries was studied in vitro. Ammonia (NH3/NH4+) caused relaxation of cerebrovascular smooth muscle which was transient and occurred irrespective of how the vessels were preconstricted (potassium-Krebs solution, noradrenaline, serotonin, prostaglandin F2 alpha). The effect was independent of ammonia-induced extracellular changes in pH. It is concluded that ammonia may contribute to the vasodilatation and increase in cerebral blood flow which occurs under certain pathophysiological conditions.
mesh_terms: D000641:Ammonia / Q000494:pharmacology*; D000818:Animals; D002536:Cerebral Arteries / Q000187:drug effects*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D011817:Rabbits; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D000641:Ammonia