title: Aging-induced changes in brain regional serotonin receptor binding: Effect of Carnosine.
abstract: Monoamine neurotransmitter, serotonin (5-HT) has its own specific receptors in both pre- and post-synapse. In the present study the role of carnosine on aging-induced changes of [(3)H]-5-HT receptor binding in different brain regions in a rat model was studied. The results showed that during aging (18 and 24 months) the [(3)H]-5-HT receptor binding was reduced in hippocampus, hypothalamus and pons-medulla with a decrease in their both Bmax and KD but in cerebral cortex the [(3)H]-5-HT binding was increased with the increase of its only Bmax. The aging-induced changes in [(3)H]-5-HT receptor binding with carnosine (2.0 μg/kg/day, intrathecally, for 21 consecutive days) attenuated in (a) 24-month-aged rats irrespective of the brain regions with the attenuation of its Bmax except hypothalamus where both Bmax and KD were significantly attenuated, (b) hippocampus and hypothalamus of 18-month-aged rats with the attenuation of its Bmax, and restored toward the [(3)H]-5-HT receptor binding that observed in 4-month-young rats. The decrease in pons-medullary [(3)H]-5-HT binding including its Bmax of 18-month-aged rats was promoted with carnosine without any significant change in its cerebral cortex. The [(3)H]-5-HT receptor binding with the same dosages of carnosine in 4-month-young rats (a) increased in the cerebral cortex and hippocampus with the increase in their only Bmax whereas (b) decreased in hypothalamus and pons-medulla with a decrease in their both Bmax and KD. These results suggest that carnosine treatment may (a) play a preventive role in aging-induced brain region-specific changes in serotonergic activity (b) not be worthy in 4-month-young rats in relation to the brain regional serotonergic activity.
authors.affiliation: Department of Biochemistry, University of Calcutta, 35, B.C. Road, Kolkata 700 019, India.
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Department of Biochemistry, University of Calcutta, 35, B.C. Road, Kolkata 700 019, India. Electronic address: mrinalkp@yahoo.com.
authors.forename: M K
authors.initials: MK
authors.lastname: Poddar
mesh_terms: D000375:Aging / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002336:Carnosine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
chemical_list: D000975:Antioxidants; D011985:Receptors, Serotonin; D012701:Serotonin; D002336:Carnosine
keywords: [(3)H]-5-HT binding; aging; brain regions; carnosine