No abstract

No abstract

Heat-acclimatized rats were exposed to an ambient temperature of 35\s=deg\C, and the effect on testicular histology, reproductive capacity and body and scrotal temperature was evaluated. Both deep body and intrascrotal temperatures of these animals were found to be higher than those of control rats maintained at 22\s=deg\C.The intrascrotal temperature in the heat-acclimatized animals and the deep body temperature in the controls were similar. Breeding experiments proved the heat\x=req-\ acclimatized animals to be capable of mating and reproducing, although at a lower rate than the controls. The heat reduced only the mating rate and fertilization. After conception, the groups showed no difference. Histological screening revealed degenerated seminiferous tubules randomly scattered in the testes of the heat-acclimatized rats although most of the tubules showed normal spermatogenesis. These localized necrotic foci resemble the overall appearance of a cross-section of a cryptorchid testis. The heat-acclimatized animals, however, maintain a body to scrotum temperature gradient which enables spermatogenesis to proceed despite the elevated temperatures.

Monoclonal antibodies directed against the cholinergic binding site of the acetylcholine receptor were found to alter the ion channel properties in cultured chick "myoballs." Time and dose dependent reduction in acetylcholine sensitivity was observed. Noise analysis experiments indicated a decrease in the mean single channel conductance and an increase in the mean single channel open time.

No abstract