Neuropeptides and XXXX .

@entity1 @entity4545 @entity410 @entity1510 @entity739 @entity302 @entity701 @entity2359
There are four lines of evidence for or against a role of neuropeptides in @entity302 : Administration of a variety of opiate agonists into the ventricles or brain of animals produces a constellation of electrical and behavioral changes, seemingly receptor-specific, both sensitive to the specific opiate antagonist @entity1510 as well as certain anticonvulsant drugs. The primary reservation concerning these data in terms of their relevance to @entity302 regards the fact that the peptides are exogenously administered in relatively high doses. Hence, these data may reflect @entity2359 effects of peptides rather than physiologic function. A variety of opiate agonists are anticonvulsant and @entity1510 shortens the postictal state in some experimental @entity410 models. One could attempt to reconcile these data with those in No. 1 by hypothesizing that the spikes and behavioral changes examined in the latter experimental parodynes represented a sort of isolated model of the postictal state. @entity1510 has little effect in clinical @entity302 . These data are far from conclusive for two reasons. First, few @entity1 have been studied. Second, because of the issue of opiate receptor heterogeneity and the high doses of @entity1510 needed experimentally to block non-mu opiate effects, the doses of @entity1510 used clinically to date are too low to rule out possible delta- or epsilon-mediated effects. The negative clinical data are illustrative of the dangers and difficulties of extrapolating data generated in animal models of @entity410 to the @entity1 condition. ACTH, a peptide that is derived from the same precursor molecule as @entity4545 , is clearly an effective anticonvulsant in certain childhood @entity410 states. However, whether this is due to a direct or indirect (that is, @entity701 ) effect on brain is far from clear. Paradoxically, in contradistinction to other data concerning pro- and anticonvulsant properties of various opioid peptides, there is no animal model of @entity739 to help resolve this important question.
