title: The influence of gender and age on neonatal rat hypothalamic 5-HT1A and 5-HT2A receptors.
abstract: 1. Rat hypothalamic 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) concentrations are transiently sexually differentiated in the second week postpartum (pp), with higher levels in the female. In this report we investigate the possibility that 5-HT receptors may also exhibit sexual dimorphism in the neonatal period. 2. 5-HT1A and 5-HT2A receptors were quantitated by radioligand binding of [3H]ketanserin and [3H]8-OH DPAT, respectively, in hypothalamus and amygdala from male and female rats at days 8-16 pp. 3. There was no sexual dimorphism or change in the density of 5-HT2A binding in hypothalamus or amygdala over days 8-16 pp. There was also no sexual dimorphism of 5-HT1A receptors. 4. There was an increase in 5-HT1A receptor density in both the hypothalamus and the amygdala. In the hypothalamus, but not the amygdala, this increase was interrupted on day 14 by a decrease in 5-HT1A receptors, which we suggest may be of physiological significance in modifying the eventual pattern of adult agonistic activity. 5. The results suggest that the sexual dimorphism in 5-HT turnover is predominantly presynaptic, relating to altered synthesis and/or release, and is not of sufficient magnitude or duration to produce adaptive responses in postsynaptic 5-HT1A or 5-HT2A receptors.
authors.affiliation: Department of Obstetrics & Gynaecology, St. George's Hospital Medical School, London, U.K.
authors.forename: P F
authors.initials: PF
authors.lastname: Ferrari
authors.forename: S
authors.initials: S
authors.lastname: Lowther
authors.forename: H
authors.initials: H
authors.lastname: Tidbury
authors.forename: P
authors.initials: P
authors.lastname: Greengrass
authors.forename: C A
authors.initials: CA
authors.lastname: Wilson
authors.forename: R W
authors.initials: RW
authors.lastname: Horton
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000679:Amygdala / Q000254:growth & development / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007031:Hypothalamus / Q000254:growth & development / Q000378:metabolism*; D007650:Ketanserin / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009928:Organ Specificity; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000096:biosynthesis* / Q000235:genetics; D044263:Receptors, Serotonin, 5-HT1; D012727:Sex Characteristics; D013739:Testosterone / Q000502:physiology
chemical_list: D009419:Nerve Tissue Proteins; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D013739:Testosterone; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D007650:Ketanserin