Central Nervous System Distribution of Vasopressin, Oxytocin, and Neurophysin

The Hypothalamic Paraventricular Nucleus: Relationship to Brain and Pituitary Pools of Vasopressin and Oxytocin as Compared to Dynorphin, β-Endorphin and Related Opioid Peptides in the Rat

“…This observation is in confirmation of prior neuroanatomical studies in indicat ing the existence of a VP and OT projection from the PVN to the NIL in the rat [8, 37,39,40]. Previous reports would suggest that the SON is responsible for the majority of the ir-VP and ir-OT persisting in PVN-lesioned animals [8,27,39,40].…”

“…Immunohistochemical and other neuroanatomical investigations have not, as yet, thoroughly resolved the individual contributions of the PVN, SON and SCN to these extrahypothalamic networks. The PVN has, nevertheless, been implicated as a significant origin of the VP-and OT-innervation of a number of structures includ ing, for example, the medulla/pons [3,38,39,42].Recently, a variety of studies have addressed the ques tion of the possible existence of an interrelationship of OT, or, in particular, VP, with endogenous opioid peptides at either pituitary or CNS loci.It has, firstly, been shown that both opioid peptides and alkaloids suppress the secretory activity of VP-and OT-containing magnocellular neurons travelling to the neural lobe …”

“…It has emerged that VP and OT are not confined to a hypothalamo-neurohypophyseal axis but are widely distributed throughout the CNS in neuronal pathways derived from the hypothalamus, the functional significance of which is ob scure [3, 8, 32,[38][39][40]42). Immunohistochemical and other neuroanatomical investigations have not, as yet, thoroughly resolved the individual contributions of the PVN, SON and SCN to these extrahypothalamic networks.…”

“…(3) although coexisting with ir-VP in a hypothalamo-neural lobe tract partially derived from the PVN, ir-DYN, ir-D Y N ,and ir-a-NE exist independ ently of the PVN-originating VP-containing neurons which innervate extrahypothalamic brain tissue. (4) the PVN may in teract with hypothalamic ir-P-EP and plays a facilitatory role in the tonic regulation of adenohypophyseal secretion of irp-EP into the systemic circulation.The paraventricular, supraoptic and suprachiasmatic nuclei (PVN, SON and SCN) of the hypothalamus, in addi tion to a few accessory cell clusters, comprise the perikaryal sites of synthesis of the 'classical' neurohypophyseal nonapeptides, vasopressin (VP) and, with the exception of the SCN, oxytocin (OT) [3, 8,39,40,42], It is the PVN and SON which, in distinction to the SCN, provide the majority of the VP-and OT-containing neurons that project to the neural lobe of the pituitary, from which VP and OT are se creted into the systemic circulation [3, 8,37,39,40]. It has emerged that VP and OT are not confined to a hypothalamo-neurohypophyseal axis but are widely distributed throughout the CNS in neuronal pathways derived from the hypothalamus, the functional significance of which is ob scure [3, 8, 32,[38][39][40]42).…”

Influence of vasopressin and angiotensin on baroreflexes in the dog.

“…Matsuguchi et al (1982) have reported dose-related blood pressure and heart rate increases with AVP injections into the nucleus tracrus solitarius. There is neuroanaiomical evidence for AVP efferent monosynaptic axon projections from the paraventricular nucleus to the brainstem and spinal cord (Swanson, 1977;Ciriello and Calaresu, 1980a;Ciriello and Calaresu, 1980b;Sofreniew and Weindl, 1981;Zimmerman, 1981). Although the organization and function of these pathways remain obscure, these studies, together with the present observations, represent increasing evidence for potential central actions of AVP on autonomic pathways.…”