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Open Access Thesis

Keywords

Rats--Physiology; Sodium in the body; Taste--Physiological aspects;

Abstract

Previous research has demonstrated strain differences in sodium intake as well as strain-dependent effects of early experience on the sodium intake of rats. The present study investigated the roles of prenatal and postnatal maternal environment in determining the sodium intake patterns of hybrid offspring resulting from the reciprocal crossing of two inbred rat strains known to differ in sodium consumption: TS3 (high intake) and I (low intake). Offspring of identical genetic makeup were first subjected to differing prenatal maternal environments (TS3 or I). At birth the crossbred pups were either cross-fostered to a host dam of the opposite strain or handled and returned to their biological mother, allowing manipulation of postnatal maternal environment as well. Pups and dams were then left undisturbed until weaning, at which time the intake of 0.9% saline and water, and then 3.0% saline and water were examined in two-bottle preference tests, each lasting approximately one week. The animals were retested as adolescents and again as adults. Saline and water intake during food deprivation and the percentage daily fluid intake made up by saline were also noted for the male and female animals at all three ages. Thus, the present study is a longitudinal investigation of the effects of in utero and/or postnatal experience with a mother of a high sodium intake strain versus the effects of in utero and/or postnatal experience with a mother of a low intake strain on the later sodium intake of young that share the same genetic makeup. It was hypothesized that both prenatal and postnatal experience would have significant effects on later intake patterns. Results of this investigation revealed that both prenatal and postnatal maternal environments played a role in determining sodium intake under various conditions as had been predicted. These effects were more often (but not only) seen in females and the largest differences in intake were seen when comparing animals whose early experience was most different (that is, comparing animals both born and raised by TS3 dams to those both born and raised by I dams). Those animals with mixed early experience drank intermediate amounts of saline as hypothesized. The direction of the maternal environment effect on these hybrid offspring was not, however, that which was proposed based on previous studies of the original inbred strains. That is, the sodium intake of crossbred offspring was increased by exposure to an I (the low intake strain) maternal environment rather than a TS3 (the high intake strain) maternal environment. The general conclusion of the present study is that early experience (both prenatal and postnatal) as well as genetic makeup play a role in determining sodium preference and intake in rats.

Year of Submission

1985

Degree Name

Master of Arts

Department

Department of Psychology

First Advisor

Linda Walsh

Second Advisor

Julia Wallace

Third Advisor

Andrew R. Gilpin

Comments

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Date Original

1985

Object Description

1 PDF file (73 leaves)

Language

en

File Format

application/pdf

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