Affiliations: Department of Community and Family Health, College of
Public Health, University of South Florida, Tampa, FL, USA | Private Practice, Health and Hope Nutrition Services,
Cookeville, TN, USA | Consumer and Family Sciences, Western Kentucky
University, Bowling Green, KY, USA | Department of Poultry Science, Texas A University,
College Station, TX, USA | Department of Biology, Northern Caribbean University,
Note:  Corresponding author: Preston Mercer, Ph.D., FACN Department of
Community and Family Health, College of Public Health, University of South
Florida, 13201 Bruce B. Downs Blvd., Tampa, FL 33612, USA. Tel.: +1 813 974
9981; Fax: +1 813 974 8889; E-mail: [email protected]
Abstract: Obesity is a growing health problem because it is associated with
many diseases, such as cancer, heart disease and diabetes. There is increasing
evidence that obesity is under control of several factors in the brain,
including orexigenic and anorexigenic neuropeptides and neurotransmitters.
Histamine-containing neurons and their receptors, closely involved in
regulation of food intake, are distributed throughout the brain. In the
reported experiments, dietary influence on H1-receptor binding was examined
using female Sprague-Dawley rats fed diets of low, medium or high quality
protein, or diets of normal energy, low energy, very low energy. Differences in
food intake and weight change occurred; with no significant differences in
whole-brain H1 receptor binding such as had been seen in male rats.
Histaminergic antagonism was then tested using centrally acting antihistamines.
Weight gain was related to dietary protein intake for saline and doxepin
treated rats. Rats fed 5% protein (maintenance) demonstrated that doxepin was
a more effective histaminergic antagonist than terfenadine (peripherally
acting) in affecting mean cumulative weight gain and food intake. Dietary
protein level influenced observed outcomes for the two groups. Male and female
rats were given the choice of diets containing 0% or 60% protein, with or
without doxepin. Females chose cumulatively lower protein intake than males.
The relationship between dietary content, the histaminergic system and food
intake in female rats appears to be different than that seen previously in male
rats while Zucker obese rats showed no response in histaminergic binding. These
studies support the observation that centrally acting antihistamines can
increase weight gain.
Keywords: Histamine receptor, obesity, rat, dietary protein