Evidence for an in vivo and in vitro modulation of endogenous cortical GABA release by α-glycerylphosphorylcholine
The effects of α-glycerylphosphorylcholine (α-GPC) on endogenous cortical GABA release were studied both in vivo and in vitro. In freely moving rats, equipped with epidural cups, α-GPC (30–300 mg/kg i.p.) increased GABA release. This effect was potentiated by atropine, both systematically administered (5 mg/kg i.p.) and locally applied (1.4 μM), but not by mecamylamine (4 mg/kg i.p.). The α-GPC-induced increasein GABA release was abolished in rats pretreated with the α1 receptor antagonist prazosin (14 μg/kg i.p.). In cortical slices α-GPC (0.4 mM) increased the spontaneous GABA efflux. This effectwas abolished by tetrodotoxin (0.5 μM) and prazosin (1 μM), but not by atropine (0.15 μM) ormecamylamine (2.5μM). These results indicate that the facilitatory response by α-GPC on GABArelease does not depend on a direct activation of either muscarinic or nicotinic receptors, but suggest the involvement of the noradrenergic system.
Key wordsEpidural cups cortical slices GABA release rat neurotransmitter interactions
Unable to display preview. Download preview PDF.
- 4.O’Neill, C., Marcusson, J., Nordberg, A., and Winblad, B. 1987. The influence of age on neurotransmitters in the human brain. Pages 183–198,in Govoni, S., and Battaini, F. (eds.) Modification of cell to cell signals during normal and pathological aging. Springer-Verlag, Berlin, Heidelberg.Google Scholar
- 5.Finali, G., Piccinin, M., and Piccirilli, M. 1992. Le basi neurochimiche della terapia farmacologica delle demenze. Parte seconda: aminoacidi e peptidi. Basi Raz. Ter. 22 (2):99–121.Google Scholar
- 7.Manyan, N. B., Katz, L., Hare, T. A., Gerber, J. C., and Grossman, M. H. 1980. Levels of γ-aminobutyric acid in cerebrospinal fluid in various neurologic disorders. Arch. Neurol. 37:352–355.Google Scholar
- 22.Moroni, F., Tanganelli, S., Antonelli, T., Carla’, V., Bianchi, C., and Beani, L. 1983. Modulation of cortical acetylcholine and γ-aminobutyric acid release in freely moving guinea pigs: effect of clonidine and other adrenergic drugs. J. Pharmac. Exp. Ther. 227: 435–440.Google Scholar
- 24.Raiteri, M., Marchi, M., Paudice, P., and Pittaluga, A. 1990. Muscarinic receptors mediating inhibition of gamma-aminobutyric acid release in rat corpus striatum and their pharmacological characterization. J. Pharmacol. Exp. Ther. 254:498–501.Google Scholar
- 25.Ferraro, L., Tanganelli, S., and Beani, L. 1994. Muscarinic (M2) mediated inhibition of the electrically-evoked endogenous GABA release from guinea pig cerebral cortex slices. Pol. J. Pharmacol. 46:308–309.Google Scholar
- 27.Beani, L., Bianchi, C., Tanganelli, S., Antonelli, T., Simonato, M., and Rando, S. 1988. Inversion of alpha-2 and alpha-1 noradrenergic control of the cortical release of acetylcholine and gamma-aminobutyric acid in morphine-tolerant guinca pigs. J. Pharmacol. Exp. Ther. 247:294–301.PubMedGoogle Scholar