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Activation of the rat melanin-concentrating hormone neurons by ventromedial hypothalamic lesions
A Deray1, B Griffond, C Colard
1CNRS UA 561, Laboratoire d'Histologie Embryologie Cytogénétique, Faculté de Médecine, Besançon, France.
Abstract:
The occurrence of a melanin-concentrating hormone-like peptide (MCH) was previously reported in the lateral hypothalamus of the rat. The sequence of this peptide was determined but its role as well as its regulation remain unclear. In the present study, we examined the effects of minor electrolytic lesions of the ventromedial nuclei (VMN) on MCH neurons by using immunocytochemical and in situ hybridization procedures. We report that VMN lesions resulted in (1) a clear elevation in the number and staining intensity of MCH immunoreactive perikarya and fibres, (2) a significant increase in the level of hybridocytochemical signal obtained with an oligonucleotide probe complementary to rMCH mRNA. These data provide evidence for a role of VMN in modulating the MCH gene a peptide expression.
Insights
Ventromedial nuclei lesions increase melanin-concentrating hormone (MCH) peptide expression in rats. This study reveals the ventromedial nuclei
Area of Science:
- Neuroscience
- Neuroendocrinology
- Molecular Biology
Background:
- Melanin-concentrating hormone-like peptide (MCH) is found in the rat lateral hypothalamus.
- The precise role and regulation of MCH remain largely unknown.
Purpose of the Study:
- To investigate the influence of ventromedial nuclei (VMN) on MCH neurons.
- To understand the regulatory mechanisms of MCH gene and peptide expression.
Main Methods:
- Electrolytic lesions were made in the ventromedial nuclei (VMN) of rats.
- Immunocytochemistry was used to assess MCH perikarya and fibers.
- In situ hybridization with an oligonucleotide probe measured rMCH mRNA levels.
Main Results:
- VMN lesions led to increased MCH immunoreactive perikarya and fibers.
- A significant rise in hybridocytochemical signal for rMCH mRNA was observed.
- These findings indicate VMN modulates MCH gene and peptide expression.
Conclusions:
- The ventromedial nuclei play a significant role in regulating MCH expression.
- VMN lesions upregulate both MCH peptide and mRNA levels.
- This provides crucial insights into the neuroendocrine control of MCH.