TESTING THE EFFECTS OF THE IMIDAZOPYRIDINE ZOLPIDEM ON MEMORY:AN ECOLOGICALLY VALID APPROACH

The present study explores whether memory impairments are found on the morning following intake of the hypnotic zolpidem which is a member of a new pharmaceutical class, the imidazopyridines. The procedure used is novel: it involves testing subjects in their own homes via the telephone. A previous study using this technique found significant deficits in performance on the morning following intake of the benzodiazepines, flunitrazepam and midazolam, on tasks which load heavily on both the speed and capacity aspects of the human information processing system. Using the same tests, results from the present study fail to find any significant effects on the morning following zolpidem intake

Electrical stimulation releases 3H-betaxolol from rat atrial slices: Possible role of noradrenergic nerves

Under in vitro conditions, 3H-betaxolol was accumulated in rat atrial slices, reaching a tissue-medium ratio of 12.3±1.8 ml/g. This process was temperature-dependent, but ouabain-resistant. 3H-Betaxolol accumulated in atrial slices was subsequently released by electrical stimulation. The electrically-evoked release of 3H-betaxolol was abolished in the absence of calcium, and reduced in the presence of bretylium 10 μM. After surgical sympathetic denervation by stellate ganglionectomy there was a marked reduction in the endogenous content of noradrenaline and in the retention of 3H-noradrenaline in atrial slices. The concomitant decrease in the amount of 3H-noradrenaline released by electrical stimulation following denervation was modest, although statistically significant. Following sympathetic denervation, the tissue retention of 3H-betaxolol was not significantly affected, but the release of 3H-betaxolol by electrical stimulation was considerably reduced. After pretreatment with reserpine the amount of radioactivity released by electrical stimulation from slices labelled with 3H-betaxolol or 3H-noradrenaline was markedly reduced. The tissue retention of 3H-noradrenaline was reduced to a larger extent than that of 3H-betaxolol following the administration of reserpine. The simultaneous release of noradrenaline and betaxolol by nerve stimulation observed under our experimental conditions may represent a mechanism through which betaxolol can reach selectively the postsynaptic β1-adrenoceptors and reinforce β-adrenoceptor blockade in the heart. © 1986 Springer-Verlag