title: Thermal alterations in onset and offset rate constants for chlorpheniramine.
abstract: The onset and offset rate constants for chlorpheniramine were obtained using the longitudinal muscle of guinea pig ileum. Between 21 degrees C and 37 degrees C these values follwed linear Arrhenius plots with activation energies similar to other biological systems. Below 18 degrees C the nature of the antagonism changed prohibiting estimation of the rate constants. It is concluded that at higher temperatures the histamine receptor behaves in a uniform manner, but below 20 degrees C a change in properties occurs.
mesh_terms: D000818:Animals; D002744:Chlorpheniramine / Q000494:pharmacology*; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D013696:Temperature; D013997:Time Factors
chemical_list: D002744:Chlorpheniramine; D006632:Histamine