The role of vasopressin in olfactory and visual processing

Abstract

Neural vasopressin is a potent modulator of behaviour in vertebrates. It acts at both sensory processing regions and within larger regulatory networks to mediate changes in social recognition, affiliation, aggression, communication and other social behaviours. There are multiple populations of vasopressin neurons within the brain, including groups in olfactory and visual processing regions. Some of these vasopressin neurons, such as those in the main and accessory olfactory bulbs, anterior olfactory nucleus, piriform cortex and retina, were recently identified using an enhanced green fluorescent protein-vasopressin (eGFP-VP) transgenic rat. Based on the interconnectivity of vasopressin-producing and sensitive brain areas and in consideration of autocrine, paracrine and neurohormone-like actions associated with somato-dendritic release, we discuss how these different neuronal populations may interact to impact behaviour.

The Biology of Vasopressin

“…In contrast, the parvocellular neurons project from the PVN to the median hypothalamic eminence, and release AVP to trigger the secretion of ACTH and several anterior pituitary hormones [ 172 , 175 ]. Other AVP-synthesizing neurons can be found in the medial amygdala, the bed nucleus of the stria terminalis (BNST), and the SCN, which all project centrally to the brain preoptic and olfactory areas, hypothalamic, and extra-hypothalamic regions [ 54 , 176 , 177 , 178 ]. These neurons are thought to be the source of neural AVP because the blood brain barrier is impermeable to plasmatic AVP [ 166 , 179 , 180 , 181 ].…”

“…To probe the AVP neural functions in vivo, gene knock-out of AVP or its receptors and pharmacological targeting of AVP receptors have been employed in combination with behavioral tests such as the forced swim test, which assesses the animal’s overwhelm from a prolonged drowning threat and the elevated plus maze test that measures anxiety ([ 43 ], reviewed in [ 197 ]). In such contexts, the AVP response appeared largely subject-specific and influenced by social experience, hormonal status, and the neuronal connections within the hypothalamus and between the hypothalamus and other areas [ 178 , 198 , 199 ].…”

“…In rodents, species-specific recognition is largely based on olfactory cues, and depends on species-specific distribution of AVP-immunoreactive nerve fiber types [ 213 ]. Pharmacological or genetic V1aR targeting prevented short-term social recognition in rats, possibly through changes in olfactory processing [ 178 , 214 , 215 ].…”

“…To study the effects of AVP in human subjects, intra-nasal administration is used in combination with functional MRI (fMRI) to reveal the brain areas with changes in deoxyhemoglobin concentration in response to AVP [ 33 , 178 , 295 , 296 ]. As in animals, intranasal AVP administration may increase endocrine stress by augmenting amygdala activity [ 165 ] and promoting ACTH secretion [ 167 ] and favor negative responses in ambiguous social situations [ 297 ].…”

Vasopressin & Oxytocin in Control of the Cardiovascular System: An Updated Review

“…All actions, including the cardiovascular actions of VP and OT, are mediated via specific, very similar, membrane G protein linked receptors, widely distributed in the body . The majority of central nervous system actions [35][36][37][38][39][40] and of the peripheral actions of VP including vasoconstriction [41,42], glycogenolysis [43,44] adrenal angiotensin II secretion [45] and platelet adhesion [46] are mediated via type 1 receptors (V1aR), coupled to a Gq/11 protein, phospholipases C, D and A2 as well as intracellular calcium increase [22,23]. In the kidneys, VP binds to type 2 receptors (V2R) coupled to cAMP production, and control aqaporin-2 (Aqp-2) gene expression and synthesis, affecting water reabsorption and urine concentration [47,48].…”