Isometric responses in the denervated diaphragmatic muscle of the guinea pig elicited by antigen and histamine.
Denervated diaphragmatic muscle strips from the guinea pig responded in vitro to varying concentrations of histamine with isometric contractions. Dose-response curves from strips taken from several areas of the muscle (ventral, V; dorsal, D; lateral, L) had slopes which were related in the following manner: D greater than V greater than L. Nevertheless, when the curves were normalized with respect to a dose which produced maximal tension, the slopes were similar and could be superimposed. Preparations taken from animals allergized to either bovine serum albumin or ferritin responded to the antigen with isometric contractions which also differed according to the original location of the strip in the muscle (D greater than V greater than L), but were similar when normalized as above. The results obtained from the normalized curves reflect a uniform sensitivity to histamine and antigen throughout the muscle. The variations in tension developed in the different strips probably are related to their contractile mass. The isometric recordings also revealed the development of spontaneous muscular contractions, as well as the presence of response latencies to both histamine and antigen, but not to acetylcholine.
D000818:Animals; D000941:Antigens / Q000008:administration & dosage* / Q000276:immunology; D003964:Diaphragm / Q000276:immunology / Q000294:innervation; D004305:Dose-Response Relationship, Drug; D005260:Female; D005293:Ferritins / Q000276:immunology / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000032:analysis / Q000494:pharmacology*; D006967:Hypersensitivity / Q000276:immunology; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects*; D008297:Male; D008722:Methods; D009119:Muscle Contraction / Q000187:drug effects*; D009121:Muscle Denervation; D011968:Receptors, Histamine / Q000502:physiology; D012710:Serum Albumin, Bovine / Q000276:immunology
D000941:Antigens; D011968:Receptors, Histamine; D012710:Serum Albumin, Bovine; D006632:Histamine; D005293:Ferritins