• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.155.1-155
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• 1994

No Abstract, See Full Text

• Korean Journal of Veterinary Research
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• v.44 no.2
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• pp.207-215
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• 2004

It is well known that the hypothalamic-pituitary-adrenocortical (HPA) axis is under the negative feedback control of adrenal corticosteroids. Previous studies have suggested that glucocorticoids can regulate neuroendocrine cells in the paraventricular nucleus (PVN) by modulating catecholaminergic transmission, a major excitatory modulator of the HPA axis at the hypothalamic level. But, the effects of corticosteroids on the expression of adrenoceptor subtypes are not fully understood. In this work, we examined mRNA levels of six adrenoceptor subtypes (${\alpha}_{1A}$, ${\alpha}_{1B}$, ${\alpha}_{2A}$, ${\alpha}_{2B}$, ${\beta}_1$ and ${\beta}_2$) in the PVN of normal and adrenalectomized (ADX) rats. Total RNA ($2.5{\mu}g$) was extracted from PVN micropunches of brain slices ($500{\mu}m$) and analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The levels of corticotropin-releasing hormone (CRH) mRNA were increased in the ADX rats relative to normal rats, indicating that the PVN had been liberated from the negative feedback of corticosteroids. Among the six adrenoceptor subtypes examined, mRNA levels for ${\alpha}_{1B}$- and ${\beta}_1$-adrenoceptors were increased, but the level for ${\beta}_2$-adrenoceptors was decreased in the ADX rats. The mRNA levels for the other three subtypes and for the general and neuronal specific housekeeping genes, glyceroaldehyde-3-phosphate dehydrogenase (GAPDH) and N-enolase, respectively, were not changed in the ADX rats. In conclusion, the results indicate that adrenal steroids selectively regulate the gene expression of adrenoceptor subtypes in the PVN.