[Use-dependent inhibition of C-axon multimodal units of cat skin by lidocaine and N-propyl-ajmaline]. / Zavisimoe ot primeneniia ingibirovanie C-aksonnykh polimodal'nykh edinits kozhi koshki lidokainom i N-propil-aimalinom.

Subcutaneous application of local anesthetic drug lidocaine and cardiac antiarrhythmic n-propyl-ajmaline produced the reversible use-dependent inhibition of feline polymodal mechano-heat C-fiber cutaneous sensory units (CMH-units) excited by moderate noxious mechanical stimulus. The discharge rate as well as the number of evoked spikes of polymodal sensory units treated with the drugs decreased below the values observed under noxious chemical excitation of CMH-units. The repeated mechano-stimulation with 5 to 30 sec interval between stimuli produced complete though a reversible block of the treated units. Quaternary amine n-propyl-ajmaline induced use-dependent inhibition of CMH-units in lower concentrations than tertiary amine lidocaine. The use-dependent inhibition of CMH-units is discussed in connection with nociception and local analgesia.

[Pain reception in the skin studied with chemical agents]. / Izuchenie bolevoi retseptsii v kozhe s pomoshch'iu khimicheskikh agentov.

Cutaneous C-fibre polymodal mechano-heat (CMH) sensory units of narcotized cats have been studied for their responses to the close-arterial injection of potassium, acetylcholine and methacholine to the saphenous artery in subnoxious and noxious concentrations. Subnoxious chemical stimulation has induced low-frequency excitation of CMH units. The parameters of CMH units firing during subnoxious and noxious chemical stimulation may be used for estimation of effects of local anesthetics. To achieve local anesthesia it is sufficient to inhibit only high frequency responses in CMH units without a complete block of these sensors. With that end in view the use-dependent blockers of nerve excitation are suggested. The use-dependent inhibition of CMH units was found during mechanical stimulation under the action of lidocaine or n-propylajmaline. The mathematical model of C-fibre has demonstrated the key role of slow changes of membrane ionic permeabilities in determining the firing rate elicited by chemical stimulation.