XXXX receptor-mediated inhibition of glutamate release in the arcuate nucleus of the hypothalamus.

@entity308 @entity3280 @entity141 @entity4524 @entity16424 @entity35
It is thought that galanin, a 29 amino acid neuropeptide, is involved in various neuronal functions, including the regulation of food intake and hormone release. Consistent with this idea, galanin receptors have been demonstrated throughout the brain, with high levels being observed in the hypothalamus. However, little is known about the mechanisms by which galanin elicits its actions in the brain. Therefore, we studied the effects of galanin and its analogs on synaptic transmission using an in vitro slice preparation of @entity35 hypothalamus. In arcuate nucleus neurons, application of @entity16424 resulted in an inhibition of evoked glutamatergic EPSCs and a decrease in @entity308 , indicating a presynaptic action. The fragments galanin 1-16 and 1-15 produced a robust @entity308 of synaptic transmission, whereas the fragment 3-29 produced a @entity308 . The chimeric peptides C7, M15, M32, and M40, which have been reported to antagonize some actions of galanin, all produced varying degrees of @entity308 of evoked EPSCs. In a minority of cases, C7, M15, and M40 antagonized the actions of galanin. Analysis of mEPSCs in the presence of @entity4524 and @entity3280 , or after application of alpha-latrotoxin, indicated a site of action for galanin downstream of @entity141 entry. Thus, our data suggest that galanin acts via several subtypes of presynaptic receptors to depress synaptic transmission in the @entity35 arcuate nucleus.
