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Thesis advisor: Alexa Veenema / Thesis advisor: Gorica Petrovich / Sex differences in the regulation of social behavior as well as sex biases in prevalence of social disorders such as autism are likely due to sex differences in brain function. An important candidate for investigating sex-specific regulation of social behavior is the neuropeptide arginine vasopressin (AVP). AVP shows sex differences in synthesis and fiber innervation in the brain, regulates a wide variety of social behaviors, and has been implicated in the etiology of autism. However, a systematic analysis of potential sex differences in AVP receptors in the brain and linking such parameters to sex differences in social behavior is lacking thus far. Therefore, we determined whether there are sex differences in AVP V1a receptor (V1aR) in the rat brain. We then targeted specific brain regions to determine the functional significance of such sex differences. We found that males showed higher V1aR binding densities compared to females in 6 out of 15 forebrain regions analyzed, including the anteroventral thalamic nucleus, hippocampal dentate gyrus, lateral hypothalamus, tuberal lateral hypothalamus, anterior piriform cortex, and stigmoid hypothalamic nucleus. Because of hormonal regulation of the AVP system, we also analyzed differences in V1aR binding due to estrus phase and maternal experience. Since the most robust sex difference in V1aR binding was found in the hippocampal dentate gyrus, we targeted this region to study its functional significance. Surprisingly, not only rats given an injection with a V1aR antagonist, but also vehicle-treated rats failed to show social and object recognition memory. However, social and object investigation times were normal. We therefore hypothesize that the specific impairments in memory function are likely the result of damage to other hippocampal regions due to the cannula placement. Overall, these findings demonstrate that there are significant sex differences in the V1aR in brain regions implicated in social behavior. The functional significance of these sex differences remains to be determined. / Thesis (BS) — Boston College, 2014. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Psychology Honors Program. / Discipline: Psychology.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 164-201). Also available in print.

Thesis (M.Sc. (Physiology)) -- Mahidol University, 1970.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 10, 2009). Includes bibliographical references (p. 40-55).

A problem in modern, agile aircraft is the possibility of the pilot losing consciousness during manoeuvres which can impose forces (G) many times that of gravitational acceleration. There is a possibility that the next generation of agile aircraft will exceed the level of anti-G protection presently available and the possibility of pharmacological intervention had been considered as an additional means of raising G-tolerance. Arginine vasopressin plays an active role in maintaining blood pressure, particularly in hypovolaemic situations, by its powerful vasoconstrictive action and control of heart output. As a potential G protection agent AVP has the appeal of not appearing to produce hypertension. The human centrifuge has normally been used to investigate problems of acceleration protection, but because of the hostile environment and space restraints, it has been difficult to carry out systematic biochemical investigations and lower body negative pressure has been used to simulate the cardio-vascular stress of G. The level of plasma catecholamines and arginine vasopressin has been measured during different exposure levels to lower body negative pressure and following b blockade with Propranolol combined with lower body negative pressure. No correlation could be established between peripheral circulating plasma levels of catecholamines and arginine vasopressin for any of the experimental conditions. However, dramatic oscillations in plasma noradrenaline levels were seen and a distinct pattern of arginine vasopressin secretion was observed at presyncope. The role of arginine vasopressin during syncope was investigated and small increases in plasma levels of this vasoactive hormone appeared to play a protective role in some subjects. In subsequent experiments, a bolus of arginine vasopressin was injected prior to exposure to lower body negative pressure, but this did not appear to have any effect on tolerance to lower body negative pressure and in some subjects it was positively detrimental.

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Recently developed radioimmunoassay (RIA) techniques were employed in a quantitative investigation of the release and renal actions of the avian antidiuretic hormone, arginine vasotocin (AVT) in the conscious domestic fowl. The investigation was composed of a series of three studies with goals to: (1) define the functional characteristics of the avian hypothalamo-neurohypophysial system (HNS) in terms of the extracellular osmotic and volemic stimuli that elicit release of AVT; (2) characterize responses of the HNS to the natural challenge of negative fluid balance; and (3) quantify the relative contributions of AVT-induced glomerular and tubular antidiuresis to the conservation of water by the avian kideny. Characterization of AVT secretion revealed that plasma osmolality (P(OSM)) is a primary determinant of AVT secretion by the HNS of the domestic fowl. Highly correlated and significant relationships between P(OSM) and plasma AVT (P(AVT)) exist both above and below the observed basal P(OSM) of normally hydrated birds. Analysis of the present data also suggested that the HNS is insensitive to changes in blood volume of 10% or less, since neither isotonic expansion nor reduction of blood volume altered P(AVT). The results of the fluid deprivation experiments indicate that AVT secretion is closely linked to the state of hydration during negative fluid balance in the domestic fowl. Analysis of the data indicated that increases in P(AVT) that occur with dehydration are mediated primarily by extracellular hyperosmolality and that the HNS is relatively insensitive to the simultaneous hypovolemia incurred with fluid deprivation. Comparison to the dose-response relationships between P(AVT) and glomerular and tubular mechanisms of antidiuresis over the entire range of physiological P(AVT) levels in the domestic fowl revealed that tubular mechanisms are of primary importance and glomerular mechanisms of secondary importance in the conservation of water by the avian kidney. The greatest proportion of the total AVT-induced reduction in renal water excretion occurred at low physiological P(AVT) levels and appeared to be the exclusive result of tubular mechanisms of antidiuresis. At high P(AVT) levels, glomerular and tubular mechanisms overlapped and their effects on water conservation could not be separated; however, only minor additional amounts of water were conserved by the combined actions of glomerular and tubular mechanisms. Thus glomerular mechanisms appear to have only a minor, secondary effect on water conserving ability of the avian kidney.