Neurochemistry and Biochemical Neuropharmacology Research Unit,
Department of Biochemistry, University of Karachi, Karachi; 1Department
of Biochemistry, Federal Urdu University, Karachi; §Present
Address: Department of Biochemistry, Sir Syed Medical College,
Karachi, Pakistan
Abstract
Stress produces behavioral and neurochemical deficits. To study the relationship
between adaptation to stress and macronutrient intake, the present study was
designed to monitor the effects of different diets on feed intake, growth rate
and serotonin (5-Hydroxytryptamine, 5-HT) metabolism following exposure to
restraint stress in rats. Rats were divided into four groups (n=12) as control,
sugar, protein and fat rich diet fed rats. After 5 weeks of treatment animals of
each group were divided into unrestrained and restrained animals (n=6). Rats of
restrained group were given immobilization stress for 2 hours/day for 5 days.
Food intake and growth rates of unrestrained and restrained rats were monitored
daily. Rats were decapitated on 6th day to collect brain samples for
neurochemical estimation. Results show that sugar diet fed rats produced
adaptation to stress early as compared to normal diet fed rats. Food intake and
growth rates of unrestrained and restrained rats were comparable on 3rd
day in sugar diet fed rats and on 4th day in normal diet fed rats.
Stress decreased food intake and growth rates of protein and fat treated rats.
Repeated stress did not alter brain 5-HT and 5-HIAA levels of normal diet fed
rats and sugar diet fed rats. Protein diet fed restrained rats showed elevated
brain 5-HT levels. Fat diet fed restrained rats significantly decreased brain
TRP and 5-HIAA levels. Finding suggested that carbohydrate diet might protect
against stressful conditions. Study also showed that nutritional status could
alter different behaviors in response to a stressful environment.
Key words:
Brain 5-HT,
Carbohydrate,
Fat,
Protein,
Rat,
Stress