Carpenter D O
Wadsworth Center for Laboratories and Research, New York State Department of Health and School of Public Health, Albany 12237.
Can J Physiol Pharmacol. 1990 Feb;68(2):230-6. doi: 10.1139/y90-036.
Emesis is a reflex, developed to different degrees in different species, that allows an animal to rid itself of ingested toxins or poisons. The reflex can be elicited either by direct neuronal connections from visceral afferent fibers, especially those from the gastrointestinal tract, or from humoral factors. Emesis from humoral factors depends on the integrity of the area postrema; neurons in the area postrema have excitatory receptors for emetic agents. Emesis from gastrointestinal afferents does not depend on the area postrema, but probably the reflex is triggered by projections to some part of the nucleus tractus solitarius. As with a variety of other complex motor functions regulated by the brain stem, it is likely that the sequence of muscle excitation and inhibition is controlled by a central pattern generator located in the nucleus tractus solitarius, and that information from humoral factors via the area postrema and visceral afferents via the vagus nerve converge at this point. This central pattern generator, like those for motor functions such as swallowing, presumably projects to the various motor nuclei, perhaps through interneuronal pathways, to elicit the sequential excitation and inhibition that controls the reflex.
呕吐是一种反射，在不同物种中发育程度不同，它使动物能够排出摄入的毒素或毒物。该反射可由内脏传入纤维，尤其是来自胃肠道的纤维的直接神经连接，或由体液因素引发。由体液因素引起的呕吐取决于最后区的完整性；最后区的神经元具有催吐剂的兴奋性受体。由胃肠道传入神经引起的呕吐不依赖于最后区，但可能该反射是由投射到孤束核的某些部位触发的。与脑干调节的其他各种复杂运动功能一样，肌肉兴奋和抑制的顺序可能由位于孤束核的中枢模式发生器控制，并且来自体液因素经最后区的信息和来自内脏传入神经经迷走神经的信息在此汇聚。这个中枢模式发生器，就像吞咽等运动功能的发生器一样，大概通过中间神经元途径投射到各种运动核，以引发控制该反射的顺序性兴奋和抑制。
