title: Displacement of [(3)H]GABA binding to bovine brain receptors by sulfur-containing analogues.
abstract: The displacement of [(3)H]GABA binding to GABA receptors of bovine brain cortical membranes by some sulfur-containing compounds (homothiotaurine, thiotaurine and carboxymethylcysteamine) was investigated and their potency was compared to that of other known sulfur-containing analogues of GABA, such as homotaurine, homohypotaurine and taurine. Displacement studies showed homotaurine to be more effective as a GABA displacer than homohypotaurine and homothiotaurine (IC(50): 3.9 x 10(?8), 6.7 x 10(?7) and 6.8 x 10(?7) M, respectively). Saturation experiments showed that the effect of taurine, homothiotaurine, homotaurine and homohypotaurine was due to a loss of high-affinity GABA sites (K(d) = 10.7 nM). Homotaurine seems also to interact with low-affinity sites, decreasing the affinity constant, whereas the number of binding sites remains unchanged.
authors.affiliation: Dipartimento di Scienze Biochimiche, Università di Roma "La Sapienza", Centro di Biologia Molecolare del Consiglio Nazionale delle Ricerche, P.le A. Moro 5, 00185 RomaItalia.
authors.forename: M
authors.initials: M
authors.lastname: Costa
authors.forename: L
authors.initials: L
authors.lastname: Vesci
authors.forename: M
authors.initials: M
authors.lastname: Fontana
authors.forename: S P
authors.initials: SP
authors.lastname: Solinas
authors.forename: S
authors.initials: S
authors.lastname: Dupre
authors.forename: D
authors.initials: D
authors.lastname: Cavallini