Effects of long term consumption of sugar as part of meal on serotonin 1-a receptor dependent responses.
In view of an effect of high intake of sugar on brain serotonin (5-hydroxytryptamine, 5-HT) and a role of serotonin in the regulation of appetite, the present study concerns pre and postsynaptic responses to a selective 5-HT-1A receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) following long term consumption of sugar as part of meal in rats. Sugar diet was prepared by mixing standard rodent diet and table sugar in ratio of 3:1 (w/w) and rats were fed freely on this diet for five weeks. Control rats were fed freely on standard rodent diet. After five weeks 8-OH-DPAT at a dose of 0.5mg/kg/ml was injected to both the groups to compare effectiveness of the drug to elicit hyperphagia (presynaptic response) and elicited hyperactivity syndrome (postsynaptic response). Results showed that 8-OH-DPAT-induced forepaw treading and flatbody posture were smaller in sugar than normal diet treated rats. Conversely 8-OH-DPAT-induced hyperlocomotion was greater in sugar than normal diet treated rats. 4h Food consumption was greater in sugar than normal diet treated rats while 8-OH-DPAT-induced hyperphagia significant in normal diet treated rats was not observed in sugar diet treated rats. The results show a decrease in the effectiveness of pre as well as postsynaptic 5-HT-1A receptor dependent responses following long term consumption of sugar diet. Role of serotonin receptor responsiveness on mood and impaired adaptation to stress is discussed.
Inam
Qurrat-Ul-Aen
QU
Department of Biochemistry, Neurochemistry and Biochemical Neuropharmacology Research Unit, University of Karachi, Karachi-75270, Pakistan.
Haleem
M Abdul
MA
Haleem
Darakhshan Jabeen
DJ
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000633:toxicity*; D000284:Administration, Oral; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D019422:Dietary Sucrose / Q000008:administration & dosage*; D004435:Eating / Q000187:drug effects; D006963:Hyperphagia / Q000209:etiology / Q000378:metabolism; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism; D058825:Serotonin 5-HT1 Receptor Agonists; D020230:Serotonin Syndrome / Q000209:etiology / Q000378:metabolism; D013997:Time Factors
D019422:Dietary Sucrose; D058825:Serotonin 5-HT1 Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin