Memantine attenuates cognitive impairments after status epilepticus induced in a lithium-pilocarpine model.

The capability of memantine, a noncompetitive antagonist of the NMDA receptors, to prevent impairments of cognitive functions in rats was investigated in the lithium-pilocarpine model of epilepsy. After status epilepticus, rats exhibited impaired exploratory behavior and spatial memory, and a decline of extinction of orienting behavior. Memantine administration prevented these disturbances.

[The ability of NMDA glutamate receptor blockers to prevent a pentylenetetrazole kindling in mice and morphological changes in the hippocampus].

We investigated in mice the relationship between convulsions and morphological changes of hippocampal neurons that arise in the development of pentylentetrazol (PTZ)-induced kindling. The kindling was caused by of 35 mg/kg PTZ i.p.

[The effect of ionotropic glutamate receptor antagonist on pentylenetetrazole-indused seizures in Krushinsky-Molodkina rats].

Krushinsky-Molodkina (KM) rats exhibit inherited susceptibility to audiogenic seizures and auditory stimuli induce generalized tonic-clonic seizures that resemble human epilepsy. The aim of this study was to compare the neurological manifestations of pentylenetetrazole (PTZ)-induced seizures in Wistar and KM rats to clarify the contribution of inherited susceptibility to audiogenic seizures, and to assess the anticonvulsant activity of NMDA receptor blockers memantine and IEM-1921 (1-phenylcyclohexylamine) in the PTZ-induced seizure model in KM rats. KM rats exhibited increased seizure severity relative to Wistar rats, and the death of KM rats was observed in 2.

Involvement of ionotropic glutamate receptors in the appearance of arecoline tremor in mice.

Administration of the muscarinic cholinoreceptor agonist arecoline (6 mg/kg, s.c.) to mice induced long-lasting tremor.

[Involvement of ionotropic glutamate receptors in the genesis of arecoline-induced tremor].

The muscarinic agonist arecoline (6 mg/kg, subcutaneously in mice) induced a long-lasting tremor. The inhibitory potency of non-competitive antagonists of ionotropic glutamate receptors has been studied. These antagonists are the derivatives of adamantane and phenylcyclohexyl.

Effects of ionotropic glutamate receptor channel blockers on the development of pentylenetetrazol kindling in mice.

Experiments on mice were performed to study the ability of monocationic and dicationic adamantane and phenylcyclohexyl derivatives to prevent the development of kindling induced by i.p. administration of pentylenetetrazol (Corasol, 35 mg/kg).

[Effects of blockade of ionotropic glutamate receptors on the development of pentylenetetrazole kindling in mice].

Effects of mono- and dicationic derivatives of adamantane and phenylcyclohexyl on the petyleneterazole-induced (35 mg/kg i. p.) kindling were studied in the experiments on mice.

[The effect of affinity on the type of action of ammonium compounds on skeletal muscle cholinoreceptors].

The dependence of the mode of action (agonist or antagonist) of ammonium compounds on the acetylcholine receptors (AcR) of frog skeletal muscles on their affinity for AcR was studied in experiments on musculus rectus abdominis of Rana temporaria frogs. The mode of action of the compounds proved to be dependent on the degree of the affinity and on the character of their intermolecular interactions with the receptors. The affinity of compounds of the polymethylene-bis-trimethylammonium series is determined by electrostatic and hydrophobic interaction with the AcR.

[The cholinomimetic activity of alkyltrimethylammonium compounds in experiments on the isolated mollusk neuron and on frog and chicken skeletal muscle].

As revealed by contractile reaction of frog and chick muscles and by changes in the membrane current of isolated molluscan neurone, cholinomimetic activity of alkyltrimethylammonium compounds (ATMC) in the highest in drugs with 4 and 5 methylene groups in a molecule. The decrease in the activity with the decrease in the number of methylene groups was more evident in chick muscle; the decrease in the activity due to the increase in the number of these groups was most significant in experiments on molluscan neurone. Analysis of membrane current fluctuations showed that elementary current does not depend, whereas channel open time only slightly depends on the number of methylene groups in ATMC.

[Determination of the Hill coefficient in the action of various agonists on the N-cholinoreceptors of the isolated mollusk neuron].

The Hill coefficient (2.07-2.23) of the response to low concentrations of acetylcholine and its analogues was unrelated to their cholinomimetic activity and molecular structure.

[The reaction of the N-cholinoreceptors of the isolated neuron of the mollusk Planorbarius corneus to polymethylene-bis-trimethylammonium compounds].

Experiments have been made on isolated giant neurones of the mollusc Planorbarius corneus using clamp technique at temperatures 10 and 20 degrees C. The effect of polymethylene-bis-trimethylammonium compounds with 7-18 methylene groups in the molecule (C7..

[Factors affecting the cholinomimetic activity of alkyltrimethylammonium compounds in experiments on isolated neurons of the mollusk Planorbarius corneus].

It has been shown that the elementary current is independent whereas the duration of channel opening is slightly dependent on the number of methylene groups (from 1 to 9) in the molecule of alkyltrimethylammonium compounds. However, substances with more than 4 methylene groups exhibit lower cholinomimetic activity (i.e.

[Cholinoreceptor sensitivity of the mollusk neuron and frog skeletal muscle to acetylcholine and tetramethylammonium analogs].

Studies have been made on the sensitivity of cholinoreceptors in identified isolated neuron from the pedal ganglion of the snail Planorbarius corneus and cholinoreceptors of m. rectus abdominis of the frog Rana temporaria to drugs which differ from acetylcholine by the structure either in cationic group, methylene chain, or ester group. Snail cholinoreceptors were found to be less sensitive to changes in the structure of cationic group and more sensitive to the increase in methylene chain from 3 to 4 groups, as compared to frog cholinoreceptors.

[Reaction of cholinoreceptors from an isolated molluskan neuron with analogs of acetylcholine and tetramethylammonium].

The effect of 13 acetylcholine and tetramethylammonium derivatives on cholinoreceptors of isolated neurone on the pond snail has been investigated by the analysis of membrane current fluctuations at 10 and 20 degrees C. The elementary current was independent from the agonist structure. The channel open time and its Q10 coefficient were found to be maximum for acetylcholine.

[Comparison of the cholinoreceptor and cholinesterase properties of the frog Rana temporaria and the squid Todarodes pacificus].

Studies have been made on the interaction of several groups of quartenary ammonium salts with cholinoreceptors of m. rectus abdominis of the frog Rana temporaria, and isolated m. retractor infundibuli of the octopus Todarodes pacificus, as well as with cholinesterases of the frog brain and visual ganglia of the octopus.

[Cholinergic mechanisms in the central nervous system of the sipunculoid Physcosoma japonicum].

Acetylcholine (ACh) content of the central nervous system in the sipunculid P. japonicum was estimated by application of extracts from the nervous tissue to dental retractor of the sea urchin using ACh solutions with known concentration as a standard. It was shown that the nervous tissue contains 46 (from 41 to 51) microng of ACh (calculated as cation) per 1 g of wet material.

[Cholinomimetic activity of acetylcholine and sebacinyldicholine derivatives with differing cationic group structures].

The intrinsic alpha activities and the D2 (frog, m, rectus abdominalis) concentrations were estimated for different acetylcholine and sebacinylcholine derivatives. So were also the A2 values for antagonists and the affinity constants Kc for some partial agonists. The results obtained disprove Paton's "rate-theory".