Protection by atropine of the inhibition caused by Triton X-100 on central muscarinic receptors.

Synaptosomal membranes from cat cerebral cortex were labelled with [3H]-quinuclidinyl benzylate ([3H]QNB). There was shown to be a single type of binding site with Kd = 0.34 nM, Bmax = 2.2 nmol/g protein and Hill No. = 1.01. Triton X-100 at 5 x 10(-4)% inhibited the specific binding of [3H]QNB and the inhibition was almost complete at 10(-2)%. Treatment with 2.5 x 10(-6) M atropine, followed by centrifugation washings protected the receptor site from the inhibitory action of the detergent. The protection afforded by other cholinergic drugs was less effective. The use of this technique has confirmed the results of our previous work on the possible pre- and postsynaptic location of central muscarinic receptors. These findings open the possibility for protection of other detergent-sensitive receptors and for their isolation and purification as well-defined macromolecules.

Correlation between defective motility (asthenospermia) and ATP reactivation of demembranated human spermatozoa.

Human spermatozoa treated with 0.05% Triton X-100 to remove the cell membranes became immotile but flagellar movement was reinitiated by addition of 0.06 to 1 mM adenosine triphosphate (ATP). The percentage of spermatozoa showing flagellar movement 2 minutes after addition of 1 mM ATP from men with idiopathic asthenospermia (mean +/- SD, 34 +/- 15%), oligozoospermia (17 +/- 21%), sperm autoimmunity (17 +/- 12%), vasoepididymostomy (20 +/- 22%), or idiopathic zero motility (0%) was significantly lower than with spermatozoa from normal men (54 +/- 12%). The percentage of reactivated spermatozoa was correlated with the proportion of live cells (Eosin Y stain, r = 0.602, P less than 0.001), percentage of motile cells (r = 0.761, P less than 0.001), and motility index (r = 0.759, P less than 0.001) in the same semen samples. When expressed relative to initial sperm motility, the proportion reactivated was similar for idiopathic asthenospermia (85%) and normospermia (82%). Thus, failure to produce ATP does not appear to be a frequent cause of low sperm motility in man.

Glutathione and caffeine antagonize the sperm-immobilizing effect of a vaginal contraceptive.

The concentration-dependent inhibition of Neosampoon, a vaginal contraceptive, on ejaculated human sperm motility was studied with a transmembrane migration method. Caffeine (5mM), glutathione (5mM) and glutathione (15mM) all reactivated the motility of Neosampoon-immobilized sperm. Caffeine (5mM) was more potent than glutathione in antagonizing Neosampoon; there was no difference between the potency of 5mM- and 15mM-glutathione. Human sperm motility could be a model for studying the interaction of membrane-active drugs, including the protective effect of glutathione against membrane-disrupting agents.

PIP: This study investigated the antagonizing effect of both caffeine and glutathione on the sperm-immobilizing ability of Neosampoon, a vaginal contraceptive. The transmembrane migration method, which is effective for analyzing drug effects on human sperm motility, was used. The concentration of Neosampoon that decreased sperm motility to 50% of the control ratio was obtained, and the differences between the motility-reactivating effects of 5 mM caffeine, 5 mM glutathione, and 15 mM glutathione and phosphate-buffered saline on neosampoon-treated sperm were analyzed. All 3 mixtures reactivated the motility of neosampoon-immobilized sperm; however, was more potent that glutathione. There was no difference between the potency of 5 mM and 15 mM glutathione. Glutathione appeared to reactivate the immobilized sperm rather than prevent sperm from being immobilized. It is noted that increasing sperm motility through drugs does not necessarily enhance fertility, however, since sperm structure may become disrupted. The sperm membrane appears to be the site of action shared by caffeine and glutathione, although the definite mechanisms of their effects on sperm motility remains unclear. It is suggested that human sperm motility could provide a model for studying the interaction of membrane-active drugs, including the protective effect of glutathione against membrane-disrupting agents.

Effect of probucol on triton induced hyperlipidemias in CFY rats.

The two phases of triton test have been used to find out the effect of probucol to evaluate whether it is effective cholesterol lowering agent prophylactically or therapeutically. Probucol is shown to be a better accelerator for lipid clearance in triton hyperlipidemia than clofibrate. The clearance rate of VLDL is more than that of LDL. In the first phase of triton test probucol has more effect on cholesterol synthesis than triglycerides while in the second phase of triton test probucol has more effect as a clearing agent on triglycerides than on cholesterol.

[Hypolipemic action of various drugs in rats poisoned with Triton WR 1339]. / Acción hipolipemiante de diferentes fármacos en ratas intoxicadas con Tritón WR 1339.

We have tested the hypolipaemic activity of some drugs (Chlofibrate, Procetofene, Niadenate. Phenofibrate and Piridinol Carbamate), in rats with Triton-induced hyperlipaemia. At two dose levels (200 mg/kg b. wt and 400 mg/kg b. wt). Niadenate is the most active in both cases. Piridinol carbamate and phenofibrate show a similar activity, being able to decrease lipid levels nearly half as much as Niadenate in equal concentration of Triton 400 mg/kg b. wt. Procetofene is less active than Chlofibrate and Niadenate when Triton is used at 200 mg/kg b. wt.