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Biomedical subjects

N V Khromov-Borisov

Publications and source records attributed to N V Khromov-Borisov.

At least 19 recordsLinked to original sources
PubMed1982

A new non-depolarizing myorelaxant with high activity and specificity.

The curare-like activity and mode of action of tercuronium (p,p"-bistriethylammonium-p-terphenyl dibenzen-sulphonate) have been investigated in experiments with cats, rabbits, mice and pigeons as well as with rat phrenic diaphragm preparations. The curare-like activity of tercuronium was higher than that of tubocurarine and was close to that of pancuronium bromide. The curare-like activity of tercuronium was higher than that of tubocurarine and was close to that of pancuronium bromide. The neuromuscular blocking doses (ED95) of tercuronium, (+)-tubocurarine and pancuronium in cats, for example, were 0.08 microM/kg, 0.4 microM/kg and 0.04 microM/kg respectively. The time of development and duration of action were similar to those of (+)-tubocurarine and pancuronium. Tercuronium is a nondepolarizing myorelaxant. In experiments with cats the antagonism of neostigmine (0.1 mg/kg) to tercuronium was more pronounced than in the case of (+)-tubocurarine, pancuronium or gallamine. Tercuronium affected neither the arterial pressure nor the heart rate when given in neuromuscular blocking doses. Tercuronium did not block transmission through autonomic ganglia and had no atropine-like action. Only a 10-fold increase in the dose of tercuronium produced the ganglion blocking effect in cats. Under artificial respiration, cats and rabbits tolerated tercuronium in a dose 200 times exceeding its myoparalytic dose. It is concluded that tercuronium is distinguishable from (+)-tubocurarine by its high neuromuscular blocking activity as well as by its specificity and more pronounced neostigmine antagonism.

Anesthesia↗
PubMed1980

Interaction between acetylcholine and other agonists at cholinoreceptive membrane of mollusc neurons.

The effect of pretreatment with agonists of various chemical structure on acetylcholine action at isolated Limnaea stagnalis neurones was studied. Threshold concentrations of monoquaternary agonists or dicholinic ester of adipinic acid increase and inhibit the responses to low and high acetylcholine concentrations respectively. In contrast, suberyldicholine and compound IEM-1054 (containing two charged ammonium groups in a molecule with an internitrogen distance of 2.0-2.2 nm) decrease the action of any acetylcholine concentration. The results are discussed in terms of the cooperativity model of acetylcholine receptors (AChR) and the hypothesis about regular arrangement of AChRs in the membrane, the so called 'C-16 structure'.

Acetylcholine↗
PubMedDate not supplied

[Characteristics of chemical structure of analogs of the antimalarial drug chloridine (pyrimethamine), detetermining their teratogenic properties].

On an example of substituted 2,4-diaminopyrimidines containing at the 6th position hydrogen, alkyl radicals with a varying length of chains, ramified isoalkyl radicals and aromatic nuclei it is shown that the teratogenous activity is inherent only in some agents, being related to the chemical structure and conformation of the molecules. Accordingly, the principles of elective toxicity lying at the root of current chemotherapy may be extended also to teratology. From this it follows that there exists as a matter of principle the possibility of a purposeful synthesis of new medical compounds that would be devoid of teratogenous activity, but were endowed with valuable curative properties.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

[Cholinesterase hydrolysis of acetylcholine derivatives with different structures of the ammonium grouping].

15 acetoxyethylenammonium compounds are studied as substrates for acetylcholinesterase (ACE) from bovine erythrocytes and for butyrylcholinesterase (BCE) from horse serum. Substitution of methyl groups of the ammonium grouping with other radicals and incorporation of onium nitrogen in the cycle resulted in the decrease of the hydrolysis rate under the action of BCE and ACE, the effect of BCE being more pronounced. The rate of the hydrolysis of N-acetoxyethylene-N-methylpiperidine iodide in the presence of ACE was 65 times as much as in the presence of BCE. This compound is a new specific substrate of ACE. Dipropylmethyl derivative turned not to be a good substrate for both enzymes. Dibutylmethyl and pyridinic derivatives were not attacked by ACE and BCE. Kinetic analysis of the compounds listed is performed, taking account of non-productive sorbtion. Possible role of hydrofobic regions in the orientation of substrates on the active surface of ACE and BCE is discussed.

Acetylcholine↗
PubMedDate not supplied

[A theoretical conformational analysis of several substrates of cholinesterase having a cyclic ammonium group structure].

Conformational possibilities of pirrolidine analogues of acetylcholine beta-(N-methyl pirrolidinium)-ethyl ester of acetic acid and beta-(N-ethyl pirrolidinium)-ethyl ester of acetic acid and beta-(N-ethyl pirrolidinium)-ethyl ester of acetic acid were investigated by the method of atomic potentials. The conformational energy was considered as a sum of non-bonded and electrostatical interactions, torsional energy and distortions of bond angles. It has been shown that the replacement of the nitrogen methyl group to ethyl group results in decrease of the average barrier height between two gauche conformations of the O--C--C--N fragment. Comparison of conformational properties of some cholinesterase substrates permit to draw a suggestion that the barrier height influences the rate of the enzymatic hydrolysis.

Acetylcholine↗
PubMedDate not supplied

[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". The relationship between the cholinergic activity and the volume of cationic groups was studied and it could not possibly be explained by the steric hindrance alone. It is suggested that certain hydrophobic radicals of the cationic groups contact the receptor surface outside the anionic centre. Such contacts prevent the cholinoreceptor to change its conformation and thus inhibit the depolarization of the membrane. An approximate estimation of the anionic site dimensions is given.

Abdominal Muscles↗