The involvement of serotonin (5-HT) receptor subtypes in motor activity of the ex vivo vascularly perfused rat duodenum was investigated. Clusters of phasic contractions (CPCs), migrating in an oral to anal direction, were obtained without any stimulation. Drug effects were evaluated by changes in different components of the pressure waves, such as motor index (MI), frequency, amplitude and duration of the CPC. The effect of 5-HT depletion on motor activity was examined in animals treated with p-chlorophenylalanine (PCPA). The MI, frequency and duration of CPC were decreased by PCPA, but the amplitude was not affected, suggesting that endogenous 5-HT may play an important role in regulation of the motor activity of the rat intestine. The importance of the 5-HT receptor subtypes in the regulation of motor activity was examined. Neither the nonselective 5-HT1 and 5-HT2 receptor antagonist, methysergide, nor the 5-HT2 receptor antagonist, ketanserin, affected motor activity. However, the 5-HT3 receptor antagonists, granisetron and azasetron, decreased percentage MI, frequency, percentage amplitude and percentage duration of CPC. The 5-HT4 receptor antagonist, SB204070, exerted both excitatory and inhibitory actions, with a higher dose (10 nM) stimulating percentage MI, frequency, percentage amplitude and percentage duration, and a lower dose (0.1 nM or 1 nM) decreasing percentage MI and percentage duration of CPC. These results suggest that endogenous 5-HT regulates the motor activity of the rat duodenum through 5-HT3 and 5-HT4 receptors, with the former mediating the stimulatory influence and the latter mediating both stimulatory and inhibitory influences.

A new super junction trench MOSFET which has n-huffer regions hetween trench gates and n columns was designed and demonstrated. In this structure, the speeiSc nn-resistance (RON) does not increase as long as the trench gate

Fetal chicks were made opiate-dependent by injections of N-desmethyl-1-alpha-acetylmethadol into the chorioallantois on day 3 of embryogenesis. The injections had no effect on subsequent hatchability; however, spontaneous fetal motility was significantly depressed. Injection of naloxone caused a significant increase in the motility of the opiate-exposed fetuses but had no effect on control fetuses. That naloxone's effect was an expression of opiate withdrawal and not due to antagonism of depressed motility is also supported by the observation that naloxone significantly reduced the hatchability of opiate-exposed chicks and not of control chicks. Thus the withdrawal of a developing organism from a narcotic may be more deleterious to its survival than continued exposure.

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