Beneficial effects of a protein free, high carbohydrate meal on rat coping behavior and neurotransmitter levels during heat stress.
This study examined effects of a single protein-free (PROT-free), high carbohydrate meal (0% protein, 82% carbohydrate) or control meal (20% protein, 62% carbohydrate) on coping behavior and neurotransmitter levels of male Fischer 344 rats. Meals varying in protein/carbohydrate ratio differentially affect transport of neurotransmitter precursors into the brain and alter neurotransmission. The meals were studied in animals exposed to heat stress and normothermic control animals. Coping behavior was assessed using the Porsolt swim test (N = 39). In other rats, dopamine (DA), epinephrine (EPI), norepinephrine (NE) and serotonin in the striatum were assessed using in vivo microdialysis (N = 35). In control-fed rats, heat stress impaired Porsolt performance in comparison to normothermic controls (p <0.05). The PROT-free, high carbohydrate meal protected animals from adverse effects of stress on coping performance as it reduced the effect of heat stress more than 90%. Significant changes in striatal DA and EPI efflux were observed as a consequence of the nutritional manipulation and heat exposure. It is concluded a single PROT-free, high carbohydrate meal improves ability to cope with heat stress and alters neurotransmission. The neurochemical basis for these effects may be a change in DA efflux, although other mechanisms cannot be ruled out.
Yeghiayan
Sylva K
SK
Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA.
Georgelis
James H
JH
Maher
Timothy J
TJ
Lieberman
Harris R
HR
D000223:Adaptation, Psychological / Q000502:physiology*; D000818:Animals; D003342:Corpus Striatum / Q000737:chemistry; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004298:Dopamine / Q000032:analysis; D004837:Epinephrine / Q000032:analysis; D005502:Food; D006358:Hot Temperature; D008297:Male; D017551:Microdialysis; D018377:Neurotransmitter Agents / Q000032:analysis*; D009638:Norepinephrine / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D012701:Serotonin / Q000032:analysis; D013312:Stress, Physiological / Q000503:physiopathology*; D013550:Swimming
D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D018377:Neurotransmitter Agents; D012701:Serotonin; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine