Cardiorespiratory, sympathetic and biochemical responses to T-2 toxin in the guinea pig and rat.
The cardiorespiratory, sympathetic and biochemical effects of T-2 toxin were examined in conscious rats and guinea pigs. The pithed rat preparation was also used to evaluate possible direct effects of T-2 on the heart and vasculature. Injection of T-2 (0.5-2.0 mg/kg i.v.) into conscious rats produced prolonged (6-8 hr) hypertension and tachycardia, followed by hypotension. Total peripheral resistance was increased and cardiac output decreased. In guinea pigs, a steady decrease in pressure and rate occurred. Intravenous administration of T-2 to pithed rats did not alter blood pressure or heart rate at a time when, in conscious rats, both blood pressure and heart rate were increased. Significant elevations of arterial plasma norepinephrine, epinephrine and dopamine occurred after T-2, with metabolic acidosis, hypocarbia and hyperoxemia in both conscious rats and guinea pigs. In the rat, increase in plasma vasopressin and prostacyclin were elevated, but thromboxane and leukotriene C4-immunoreactivity were not changed. In pithed rats, T-2 did not increase basal or stimulated plasma catecholamines but produced the same changes in blood gases, pH and lactate. The LD50 values for i.v. T-2 in the rat and guinea pig were 0.74 and 1.30 mg/kg, respectively. The data are consistent with the hypothesis that T-2 toxin disrupts cellular aerobic metabolism, resulting in lactic acidosis, sympathoadrenomedullary activation, variable initial circulatory responses and eventual cardiovascular collapse.
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D001127:Arginine Vasopressin / Q000097:blood; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002395:Catecholamines / Q000097:blood; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D006400:Hematocrit; D006439:Hemodynamics / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D009490:Neurosecretory Systems / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects*; D012717:Sesquiterpenes / Q000494:pharmacology*; D013116:Spinal Cord / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013605:T-2 Toxin / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D001095:Arachidonic Acids; D002395:Catecholamines; D007773:Lactates; D012717:Sesquiterpenes; D001127:Arginine Vasopressin; D019344:Lactic Acid; D013605:T-2 Toxin