Journal of neuroendocrinology
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J. Neuroendocrinol. · Aug 1999
Leptin receptor- and STAT3-immunoreactivities in hypocretin/orexin neurones of the lateral hypothalamus.
Hypocretins/orexins are recently characterized peptides that are synthesized in neurones of the lateral hypohalamus and stimulate food intake in rats. To clarify whether leptin may interact with hypocretin/orexin to reduce ingestive behaviour, the presence of leptin receptor-immunoreactivity in hypocretin/orexin-containing neurones was examined. Many leptin receptor-and hypocretin/orexin-immunoreactive neurones were demonstrated in the lateral hypothalamic area and perifornical region. ⋯ Galanin neurones were also seen to contain leptin receptor-and STAT3-immunoreactivity. Melanin-concentrating hormone (MCH)-containing neurones constituted a cell population within the lateral hypothalamus distinct from the one containing hypocretin/orexin-immunoreactivity, as shown by elution-restaining methodology. The presence of leptin receptor-and STAT3-immunoreactivities in hypocretin/orexin-containing neurones of the lateral hypothalamus suggests that leptin may directly regulate these hypothalamic neurones, most likely via an inhibitory action on hypocretin/orexin expression and/or secretion resulting in reduced food intake.