Jean-Pierre Riffaud

Evidence for non-adrenergic binding sites for [3H]idazoxan in the smooth muscle of rabbit urethra

The binding characteristics of [3H]idazoxan and [3H]rauwolscine, two potent alpha 2-adrenoceptor antagonists, were compared in the rabbit urethral smooth muscle. The maximal binding capacity was 6 times higher for [3H]idazoxan than for [3H]rauwolscine in male rabbits. No difference was observed for these radioligands in female rabbits. There were marked differences in the ability of alpha 2-adrenergic compounds to inhibit [3H]idazoxan and [3H]rauwolscine binding. These results were consistent with the existence of non-alpha 2-adrenoceptor sites for [3H]idazoxan in the rabbit urethral smooth muscle.

α1- and α2-adrenoceptors in the smooth muscle of mal and female rabbit urethra

Abstract [ 3 H]Prazosin and [ 3 H]rauwolscine, specific α 1 - and α 2 -antagonists respectively, were used to label α-adrenoceptors in membranes from male and female rabbit uretra. In the male rabbit, [ 3 H]prazosin bound with high affinity (K d = 0.56 nM) to a single population of sites with a capacity of 73 fmol/mg protein. [ 3 H]Rauwolscine bound with a lower affinity (K d = 2.24 nM) to another single class of sites with a capacity of 41 fmol/mg protein. The order of potencies of various adrenergic compounds in inhibiting radioligand binding suggested that [ 3 H]prazosin and [ 3 H]rauwolscine interacted in the urethra with sites having the characteristics of α 1 - and α 2 -adrenoceptors, respectively. In addition, studies on the female rabbit urethra showed that α 2 -adrenoceptor density and affinity were respectively 6 times higher and 2 times lower than in the male. No significant sex difference was observed for urethral α 1 -adrenoceptors.

Synthesis and anticonvulsant activity of some 2-(N-substituted glycylamino)-4-methyl thiazoles

Abstract During the search for new biologically active agents in the thiazole field, some 2-( N -substituted glycylamino)-4-methyl thiazoles were synthesized. Preliminary pharmacological evaluation showed that these compounds exhibited anticonvulsant activity.