Nitric oxide supplementation alleviates hyperthermia induced by intake of ergopeptine alkaloids during chronic heat stress

Intake of endophyte-infected fescue diets (E+) during heat stress results in hyperthermia. This may be due to increased peripheral vasoconstriction as a result of a reduction in nitric oxide (NO) level. Rats were exposed to 32 °C for 22 d. During the last 15 d, they received exogenous NO (molsidomine; M+; 120 mg/mL drinking water) in combination with E+ or endophyte-free diets (E−). Treatment with M+ produced ∼0.4 °C reduction in night hyperthermia due to E+ treatment (P<0.01), with no effect on day temperature (P>0.13), to suggest that NO deficiency is partially responsible for fescue toxicosis-induced hyperthermia.