The mechanical effects of rhinoceros horned viper (Bitis nasicornis) venom on the isolated perfused guinea-pig heart.
In the guinea-pig Langendorff heart preparation, addition of 0.1 mg Bitis nasicornis venom to the perfusion solution caused transient increases in heart rate (HR) and left ventricular systolic pressure (LVSP) with peak increases at 2 min. With higher doses (0.6 and 1.4 mg), these increases were followed by the return of HR to normal, significant decreases in LVSP below control values and marked increases in left ventricular diastolic pressure. Histaminergic blockade with ranitidine reduced the positive responses. The results suggest that a venom component, possibly acting on intracellular calcium movement, could be responsible for both positive and negative effects.
Dipartimento di Biologia Animale, Università di Torino, Italy.
G
G
Alloatti
D
D
Gattullo
G
G
Losano
N A
NA
Marsh
P
P
Pagliaro
P
P
Vono
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D010477:Perfusion; D011899:Ranitidine / Q000494:pharmacology; D014757:Viper Venoms / Q000494:pharmacology*
D006635:Histamine H2 Antagonists; D014757:Viper Venoms; D011899:Ranitidine