[The amiridin and tacrine modulation of the cholinoreceptor activity and plasticity of snail neurons: the phenomenology and mechanisms].

The effects of amiridine and tacrine on the membrane potential, activity and plasticity of cholinoreceptors have been studied using the recording of intracellular and transmembrane currents in identified neurons of Helix lucorum. Amiridine and tacrine (1-100 mcM) have no noticeable effects on the membrane potential of the cells. Both compounds modulate the activity of cholinoreceptors to judge from their influence on the inward current induced by the local acetylcholine (ACh) application: they increase the duration of the current with a two-phase effect on the amplitude (a short-latent intensification with a following decrease).

[The effect of amiridin and tacrine on the potassium currents in a nerve fiber].

The experiments on isolated nerve fibers from the frog Rana ridibunda have demonstrated that aminoacridine tacrin and aminocholine amiridine given in a concentration of 1 microM induced a 3-4 mV increase in the resting potential of the intact Ranvier nodal membrane depolarized by several millivolts by external source current, accompanied by a rise in the amplitude and curvature of action potential. With the voltage clamp, the two agents shifted a steady state potassium conductivity vs. the voltage curve measured in the vicinity of the resting potential in isotonic KCl solution.

[The effect of amiridin on the spectral characteristics of the human EEG].

EEG testing of 28 healthy males showed that amiridine (two tablets, each 20 mg, orally at a 45-min interval) significantly enhanced alpha stability and spectral power and decreased the stability of delta activity as compared to placebo. These effects were more pronounced in the left hemisphere at rest and in the right hemisphere during mnestic activity. The perspectives of clinical application of amiridine as an antiamnestic drug are discussed in the paper.

[The effect of amiridin on the MPTP-induced Parkinson-like syndrome in monkeys].

Development of behavioral disturbances was investigated during N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration (0,2 mg/kg, i/m, at 48 h. intervals, total dose 11.2-13.

[The effect of MPTP on the neuronal uptake of monoamines].

The results of kinetic analysis of synaptosomal uptake of dopamine, noradrenaline, adrenaline and serotonin showed the presence of their own carrier systems with high or low affinity for each monoamine. The low affinity system of the uptake of monoamines by nerve endings differs from extraneuronal one by higher affinity. MPTP noncompetitively inhibits the system of highly effective uptake of the studied monoamines by nerve endings, competitively inhibiting synaptosomal uptake with low affinity of noradrenaline, adrenaline and noncompetitively serotonin and dopamine.

[Effects of amiridin and tacrine, drugs effective in Alzheimer's disease, on synaptosomal uptake of neuromediators].

The study of the drugs effective in the treatment of cognitive deficits and memory loss associated with senile dementia of the Alzheimer's type--tacrine and amiridin, acetylcholinesterase inhibitor physostigmine and nootrop piracetam on uptake of 3H-serotonin (3H-5-HT), 3H-adrenaline (3H-AD), 3H-noradrenaline (3H-HA), 2H-dopamine (3H-DA), 3H-gamma-aminobutyric acid (3H-GABA), 3H-glutamic acid (3H-GLU), 3H-aspartic acid (3H-ASP) and 3H-glycine (3H-GLI) showed that tacrine and amiridin (5 x 10(-5) M) statistically significantly (P less than 0.05) inhibited the uptake of 3H-DA and 3H-5-HT. Physostigmine at concentration 5 x 10(-4) M statistically significantly (P less than 0.