In rats, the nitric oxide (NO)-synthase pathway is present in skeletal muscle, vascular smooth muscle, and motor nerve terminals. Effects of NO were previously studied in rat neuromuscular preparations receiving low (0.2 Hz) or high (200 Hz) frequencies of stimulation. The latter frequency has always induced tetanic fade. However, in these previous studies we did not determine whether NO facilitates or impairs the neuromuscular transmission in preparations indirectly stimulated at frequencies which facilitate neuromuscular transmission. Thus, the present study was carried out to examine the effects of NO in rat neuromuscular preparations indirectly stimulated at 5 and 50 Hz. The amplitude of muscular contraction observed at the end (B) of a 10-s... |