title: Cooling-induced contraction of guinea pig tracheal smooth muscle.
abstract: Cooling of isolated guinea pig tracheal smooth muscle from 38 to 28 degrees C over 2.25 min produced a transient contraction followed by sustained relaxation. The cooling-induced contraction was blocked either by pretreatment with ouabain at concentrations of 10(-5) M or greater or by substitution of normal physiological salt solution with K-free solution. In contrast, the contractile response to cooling was not inhibited by pretreatment with phentolamine (10(-5) M), atropine (10(-5) M), tetrodotoxin (3 X 10(-7) M), diphenhydramine (10(-5) M), cromolyn sodium (10(-3) M), indomethacin (3 X 10(-7) M), nifedipine (10(-7) M), or verapamil (3 X 10(-6) M). Addition of NaHCO3 to the bath during cooling, preventing a change in pH of the physiological salt solution, did not affect the cooling-induced contraction. It is concluded that cooling of isolated guinea pig trachea produces a transient ouabain-sensitive contraction, and that the data suggest the contraction is mediated by inhibition of Na-K-ATPase in the smooth muscle rather than through neuronal stimulation or chemical mediator release.
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D003080:Cold Temperature; D005260:Female; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D017693:Sodium Bicarbonate; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D012996:Solutions; D014132:Trachea / Q000502:physiology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001639:Bicarbonates; D012996:Solutions; D010042:Ouabain; D011189:Potassium Chloride; D017693:Sodium Bicarbonate; D014700:Verapamil; D000254:Sodium-Potassium-Exchanging ATPase; D009543:Nifedipine