Acute stress increases neuropeptide Y mRNA within the arcuate nucleus and hilus of the dentate gyrus

Neuropeptides and amphibian prey-catching behavior

In mammals, a number of hypothalamic neuropeptides have been implicated in stress-induced feeding disorders. Recent studies in anurans suggest that stress-related neuropeptides may act on elemental aspects of visuomotor control to regulate feeding. Corticotropin-releasing hormone (CRH) and alpha-melanocyte-stimulating hormone, potent an orexic peptides in mammals, inhibit visually-guided prey-catching in toads. Neuropeptide Y (NPY), an orexic peptide in mammals, may be an important neuromodulator in inhibitory pre-tectal-tectal pathways involved in distinguishing predator and prey. Melanocortin, NPY and CRH neurons project onto key visuomotor structures within the amphibian brain, suggesting physiological roles in the modulation of prey-catching. Thus, neuropeptides involved in feeding behavior in mammals influence the efficacy of a visual stimulus in releasing prey-catching behavior. These neuropeptides may play an important role in how frogs and toads gather and process visual information, particularly during stress.

Auricular acupuncture decreases neuropeptide Y expression in the hypothalamus of food-deprived Sprague-Dawley rats

The aim of the present study was to investigate whether stimulation of auricular acupuncture point has any effects on the expression of neuropeptide Y (NPY), appetite-inducing factor particularly abundant in the mammalian hypothalamus. In food-deprived condition, enhanced NPY expression was detected in both the arcuate nucleus (ARN) and the paraventricular nucleus (PVN) of the hypothalamus via immunohistochemistry in Sprague-Dawley rats. Needling the unfed rats on the auricular point resulted in decreased NPY levels in both the ARN and PVN, while it increased NPY levels in the ARN and PVN of fed rats. The present findings indicate that auricular acupuncture may affect NPY expression in the ARN and PVN of the hypothalamus.