The transition from suckling to adult ingestion is a challenge facing all young mammals. In rats, this transition is made within weeks of birth and understanding the mechanisms by which rat pups normally develop from complete dependence on the dam to completely independent intake regulation may provide valuable insight for intervention in failures to accomplish the suckling to weaning transition in mammals in general. Early in a rat pup's life, the physiological signals which modulate ingestion appear to be few, but prior to weaning pups begin to modulate their intake in response to a signal related to changes in energy metabolism. The experiments in this proposal test questions about the development of intake regulation in rat pups using this emergent metabolic responsiveness. First, the role of changes in utilization of a specific metabolic fuel (fat) is tested using several pharmacological agents known to inhibit oxidation of fatty acids at several different biochemical steps. The behavioral effects of these agents are compared to their biochemical effects to test changes in the utilization of fats affect intake in young rats. Second, because physiological signals can affect ingestion at a number of behavioral levels, the ingestive behavioral components on which metabolic signals exert their effects during development is examined to test the mechanisms by which changes in the utilization of energy are translated into changes in ingestive behavior. Further, if a signal related to changes in the utilization of energy normally modulates ingestion, then feeding induced by metabolic blockers should be similar to feeding induced by energy restriction (i.e. food deprivation). Thus, similar pre- and post-absorptive physiological signals should suppress intake stimulated by food deprivation and pharmacological blockade of metabolism. This hypothesis is tested by examining the physiological signals suppressing intake stimulated by metabolic blockers. Finally, the neural mechanisms involved in translating physiological changes related to energy utilization into increases in ingestive behavior are tested.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK055531-04
Application #
6381499
Study Section
Special Emphasis Panel (ZRG2-BPO (01))
Program Officer
Yanovski, Susan Z
Project Start
1998-08-01
Project End
2003-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
4
Fiscal Year
2001
Total Cost
$128,247
Indirect Cost
Name
Purdue University
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Swithers, Susan E; Doerflinger, Alicia; Mowery, Todd (2004) 2-Mercaptoacetate does not stimulate chow intake in periweanling rats. Physiol Behav 82:3-9
Swithers, Susan E; Baronowsky, Elizabeth; Powley, Terry L (2002) Vagal intraganglionic laminar endings and intramuscular arrays mature at different rates in pre-weanling rat stomach. Auton Neurosci 102:13-9
Swithers, Susan E; McCurley, Melissa (2002) Mercaptoacetate decreases latency to initiate independent ingestion, but not suckling, in preweanling rats. Dev Psychobiol 41:103-11
Swithers, Susan E; McCurley, Melissa (2002) Effects of 2-mercaptoacetate on ingestive behavior in 18- and 21-day-old rats. Behav Brain Res 136:511-20
Powley, T L; Martinson, F A; Phillips, R J et al. (2001) Gastrointestinal projection maps of the vagus nerve are specified permanently in the perinatal period. Brain Res Dev Brain Res 129:57-72
Swithers, S E; Melendez, R I; Watkins, B A et al. (2001) Metabolic and behavioral responses in pre-weanling rats following alteration of maternal diet. Physiol Behav 72:147-57
Swithers, S E (2000) Effects of metabolic inhibitors on ingestive behavior and physiology in preweanling rat pups. Appetite 35:25-Sep