Regulatory peptides
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Regulatory peptides · Jan 2008
Neuronal interactions between neuropeptide W- and orexin- or melanin-concentrating hormone-containing neurons in the rat hypothalamus.
Neuropeptide W (NPW) was recently discovered as the endogenous ligand for GPR7 and GPR8, which are orphan G protein-coupled receptors isolated from the porcine brain. These receptors are assumed to be involved in feeding regulation and/or energy homeostasis. Recent anatomical studies have revealed that high levels of GPR7 mRNA are distributed in the brain, including the hypothalamus and amygdala. ⋯ Given this positive identification of NPW-containing neurons in the lateral hypothalamus, we further studied the nature of interaction between NPW-containing neurons and neurons containing feeding regulating peptides such as orexin- and melanin-concentrating hormone (MCH). Very close interactions between NPW-containing nerve processes and orexin- and MCH-containing neuronal cell bodies and processes could be observed. These morphological findings strongly suggest that NPW is involved in the regulation of feeding and/or sleep/arousal behavior through orexin- and/or MCH-mediated neuronal pathways.
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Regulatory peptides · Jan 2008
Developmental expression and serotonergic regulation of relaxin 3/INSL7 in the nucleus incertus of rat brain.
Relaxin 3 or insulin like peptide 7 has been identified as a new member of the insulin/relaxin superfamily. We recently reported that relaxin 3 was dominantly expressed in the brain, particularly in neurons of the nucleus incertus (NI) of the median dorsal tegmental pons and that it might act as a neurotransmitter. In the present study we investigated the developmental expression and serotonergic regulation of relaxin 3 gene in the rat brain. ⋯ We also observed the 5-HT1A receptor localization in relaxin 3 positive neurons of the NI. This result suggests that 5-HT negatively regulates the expression of relaxin 3 gene in the NI. The function of relaxin 3 neurons in the brain is influenced by the serotonergic activity.