Abstract
Hippocampus plays an important role in cognition, neuroendocrine function and sexual behaviour. Changes of hippocampal neuropeptide and neurotransmitter concentrations are associated to behavioural changes occurring throughout reproductive life. The present study focused the attention on the presence of a neurosteroid, 5α-pregnan-3α-ol-20-one (termed allopregnanolone) in hippocampus. In particular, hippocampal allopregnanolone concentration in male and female prepubertal rats and in female rats throughout estrous cycle were evaluated. Hippocampal extracts were eluted on high pressure liquid chromatography and allopregnanolone concentration was measured by radioimmunoassay. Prepubertal male and female rats (15 days old) showed highest values which significantly decreased with advancing age (25 and 60 days) (p<0.01); the lowest hippocampal concentration of allopregnanolone was found in adult rats. Female rats on proestrus morning and afternoon showed an hippocampal allopregnanolone concentration significantly higher than on diestrus or on estrus (p<0.01), while rats on estrus showed hippocampal allopregnanolone concentration significantly lower than during other days of estrus cycle (p<0.01). These data indicate differences in hippocampal concentration of allopregnanolone between prepubertal and adult rats and throughout estrous cycle in female rats. This finding suggest a putative role of neurosteroids in the modulation of behavioral changes occurring throughout reproductive life.
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References
Robel P., Baulieu E.-E. Neurosteroids: biosynthesis and function. TEM 5: 1, 1994.
Majewska M.D. Neurosteroids: endogenous bimodal modulators of the GABAa receptor mechanism of action and physiological significance. Prog. Neurobiol. 38: 379, 1992.
Paul S.M., Purdy R.H. Neuroactive steroids. FASEB J. 6: 2311, 1992.
Baulieu E.-E., Robel P., Vatier O., Haug A., Le Goascogne C., Bourreau E. Neurosteroids: Pregnanolone and dehydroepiandrosterone in the rat brain. In: Fuxe K., Agnati L. F. (Eds.), Receptor-Receptor Interaction, A New Intramembrane Integrative Mechanism. Basingstoke, 1987, p. 89.
Purdy R., Morrow P.H., Moore P.H., Paul S.M. Stress-induced elevation of GABA receptors-active 3α-hydroxysteroids in the rat brain. Soc. Neurosci. 16: 691, 1990 (Abstract).
Bartholini G., Scatton B., Zivkovitz B., Lloyd K.G. On the mode of antidepressant action of GABA receptors agonist and monoamine-uptake inhibitors. In: Bartholini G., Lloyd K.G. (Eds.), GABA and Mood Disorders. Raven Press, New York, 1986, p. 105.
Schwartz-Giblin S., Pfaff D.W. Commentary. Integr. Psychiatr. 5: 258, 1987.
Flood J.F., Roberts E. Dehydroepiandrosterone sulfate improves memory in aging mice. Brain Res. 447: 269, 1988.
Paul S.M., Purdy R.H. Neuroactive steroids. FASEB J. 6: 2311, 1992.
Robel P., Baulieu E.-E. Neurosteroids: biosynthesis and function. TEM 5: 1, 1994.
Purdy R.H., Morrow A.L., Blinn J.R., Paul S.M. Syntesis, metabolism, and pharmacological activity of 3α-hydroxy steroids wich potentiate GABA-receptors-mediate chloride ion uptake in rat cerebral cortical synaptoneurosomes. J. Med. Chem. 33: 1572, 1990.
Corpéchot C., Young J., Calvel M., Wehrey C., Veltz J.N., Touyer G., Mouren M., Prasad V.V.K., Banner C, Sjövall J., Baulieu E.-E., Robel P. Neurosteroids: 3α-hydroxy-5α-pregnane-20-one and its precursor in the brain, plasma, and steroidogenic glands of male and female rats. Endocrinology 133: 1003, 1993.
Patchev V.K., Shoaib M., Holsboer F., Almeida O.F.K. The neurosteroids tetrahydroprogesterone counteracts corticotropin-releasing-hormone-induced anxiety and alters the release and gene expression of corticotropin-releasing-hormone in the rats hypothalamus. Neuroscience 62: 265, 1994.
Guo A.-L., Petraglia F., Criscuolo M., Ficarra G., Nappi R.E., Palumbo M.A., Trentini G.P., Purdy R.H., Genazzani A.R. Evidence for a role of neurosteroids in modulation of diurnal changes and acute stress-induced corticosterone secretion in rats. Gynecol. Endocrinol. 9: 1, 1995.
Genazzani A.R., Palumbo M.A., De Micheroux A.A., Artini P.G., Criscuolo M., Ficarra G., Guo A.-L., Benelli A., Bertolini A., Petraglia F., Purdy R.H. Evidence for a role of a neurosteroid, allopregnanolone (5α-pregnan-3α-ol-20-one), in the modulation of reproductive function in female rat. Eur. J. Endocrinol. (1995, in press).
Pfaff D.W., Schwartz-Giblin S. Cellular mechanism of female reproductive behaviours. In: Knobil E., Neill J.D. (Eds.), The physiology of Reproduction, Vol.2. Raven Press, New York, 1988, p. 1487.
Glowinsky J., Iversen L.L. Regional studies of catecholamines in the rat brain. J. Neurochem. 13: 655, 1966.
Lowry O.H., Rosebrough N.J., Farr A.L., Randall R.H. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193: 265, 1951.
Celotti F., Massa R., Martini L. Metabolism of sex steroids in the central nervous system In: DeGroot L.J. (Ed.) Endocrinology, Vol. 1. Grune & Stratton Inc., N.Y., 1979, p. 41.
Spence K.T., Plata-Salaman R.C., French-Mullen J.M.H. The neurosteroids pregnenolone and pregnenolone-sulfate but not progesterone, block Ca2+ currents in acutely isolated hippocampal CA1 neurons. Life Sci. 49: 235, 1991.
Meyer J.H., Gruol D.L. Dehydroepiandrosterone sulfate alters synaptic potentials in area CA1 of the hippocampal slice. Brain. Res. 633(1–2): 253, 1994.
Hortnagl H., Hansen L., Kindel G., Schneider B., El Tamer A., Hanin I. Sex differences and estrous cycle-variations in the AF64A-induced cholinergic deficit in the rat hippocampus. Brain Res. Bull. 31(1–2): 129, 1993.
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Palumbo, M.A., Salvestroni, C., Gallo, R. et al. Allopregnanolone concentration in hippocampus of prepubertal rats and female rats throughout estrous cycle. J Endocrinol Invest 18, 853–856 (1995). https://doi.org/10.1007/BF03349832
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DOI: https://doi.org/10.1007/BF03349832