Journal of Nippon Medical School = Nippon Ika Daigaku zasshi
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Overproduction of nitric oxide (NO) by inducible NO synthase (iNOS) plays a role in the pathophysiology of septic shock. The depression of cardiac contractility in such situations is mediated by proinflammatory cytokines, including interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The effects of two NOS inhibitors with different isoform selectivity were compared in isolated working rat hearts. ⋯ In contrast, when L-NAME was administered in the absence of IL-1beta and TNF-alpha, it depressed contractility over the 2h perfusion period by significantly reducing coronary flow. These results support current thinking that the depression of myocardial function by IL-1beta and TNF-alpha is mediated, at least in part, by an intracardiac increase in inducible nitric oxide synthase, and that in contrast to L-NAME, the decline in coronary conductance seen in cytokine-treated is not prevented by L-canavanine hearts. L-canavanine shows selective inhibition of inducible nitric oxide synthase unlike the vasopressor action of L-NAME in cytokine-treated hearts.
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It is well known that pregnancy reduces anesthetic requirements in response to various noxious stimuli. However, there have been no detailed reports concerning functional changes in nerve fibers during pregnancy. ⋯ A significant difference in CPT values on A fibers was noted between the gravid and the nongravid women, but, no significant difference in CPT values was noted in any of the nongravid women in the follicular or luteal phases. Our results support the current theory that pregnancy changes nerve fiber conduction, as indicated by an increase in CPT values especially on myelinated fibers, but does not cause changes in CPT values across the menstrual cycle.