THE IMMUNOLOGICAL IMPAIRMENT OF VASOPRESSIN (AVP) NEURONS INTO PARAVENTRICULAR NUCLEI MODIFIES AVP EXPRESSION IN SUPRACHIASMATIC NUCLEI

A monoclonal antibody (MAb) to vasopressin (AVP) inhibits the synthesi s and the release of AVP when injected near the AVP-producing neurons. In the present experiments, the AVP-MAb was microinjected near the pa raventricular (PVN) or the supraoptic (SON) neurons of the rat hypotha lamus and the AVP expression was measured in the suprachiasmatic nucle i (SCN). When microinjected near PVN, the AVP-MAb modified the AVP mRN A studied by in situ hybridization, and the AVP immunoreactive content of SCN, whereas it failed to show some effect when injected near SON. This confirms the privileged relationships between AVP-producing neur ons in SCN and PVN.