To examine the role of monoamines in regulating β-endorphin levels in discrete brain nuclei, the levels of β-endorphin-like immunoreactivity (β-ENDi) were determined in the hypothalamic nuclei of rats 2h after they were treated with monoaminergic drugs. Sulpiride decreased the levels of β-ENDi in the nucleus paraventricularis, nucleus arcuatus and median eminence. Domperidone decreased the levels of β-ENDi in the nucleus aracuatus and median eminence. L-DOPA increased the levels of β-ENDi in the nucleus anterior hypothalami and median eminence. Phenylephrine or prazosine did not alter the levels of β-ENDi. Yohimine decreased the levels of β-ENDI in the nucleus anterior hypothalami. Isoproterenol increased the levels of β-ENDi in the nucleus arcuatus, and propranolol reversed this effect. These results suggest that dopamine and noradrenaline (via β-adrenoceptors) may regulate β-endorphinergic neurons in the rat hypothalamus.
All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism
- Clinical Neurology
- Cellular and Molecular Neuroscience