Ultrastructural evidence of direct synaptic contact of catecholamine terminals with oxytocin-containing neurons in the parvocellular portion of the rat hypothalamic paraventricular nucleus.

ABSTRACT

Ultrastructural evidence of the direct interaction between catecholamine (CA) terminals and oxytocin (OX)-containing neurons in the parvocellular portion of the rat hypothalamic paraventricular nucleus was demonstrated using immunohistochemistry combined with false transmitter (5-hydroxydopamine, 5-OHDA) histochemistry. At the parvocellular portion, 5-OHDA labelled CA terminals make synaptic contact with proximal dendrites or somas of OX-positive cells, suggesting that the ascending CA system monosynaptically regulates the extrahypothalamic OX system.