LOCALIZATION OF ATP-GATED P2X(2) RECEPTOR IMMUNOREACTIVITY IN THE RATHYPOTHALAMUS

Previous pharmacological studies have indicated that ATP receptors may be involved in the regulation of physiological functions in hypothala mus. In the present study, the distribution of P2X(2) receptor in the rat hypothalamus was studied with immunohistochemistry. It was shown t hat P2X(2) immunoreactivity-positive neurons and nerve fibres were loc alized in many hypothalamic nuclei. Intense labelling of both neuronal cell bodies and nerve fibres was observed in the paraventricular nucl eus, arcuate nucleus, retrochiasmatic area, periventricular nucleus, a nd the ventral part of tuber cinereum area. In supraoptic, circular, a nd ventral tuberomammillary nuclei the neuronal cell bodies were stron gly positive, but few nerve fibres were positive. Axons with strong P2 X(2) immunoreactivity were found in the organum vasculosum of the lami na terminalis and median eminence. Some scattered positive neurons and nerve fibres were found in many hypothalamic nuclei including preopti c nucleus. The results of the present study demonstrated the existence of P2X receptors in hypothalamus, as a basis for detailed studies of die roles of P7X receptors in the regulation of hypothalamic functions . (C) 1998 Elsevier Science B.V. All rights reserved.