Local anesthetic activity of 1-(morpholino or piperidino)-2-propanol derivatives

The local anesthetic activities of 1-(morpholino or piperidino)-2-propanol derivatives were investigated. These activities were observed with nerve trunk anesthesia, rabbit's corneal anesthesia and intradermal injection anesthesia. Among these propanol derivatives, No. 24 and No. 25 which possess thioether-type sulfur were the most active and the effective potency was enhanced by increasing the dissociation constant (pKa) value in a series of the compounds. Effects on cat spinal reflex were also observed. These propanol derivatives revealed no selective depression of presynaptic depression or depression of the potential of monosynaptic reflex (MSR) and polysynaptic reflex (PSR). Procaine and lidocaine had similar actions. Effects on axonal membrane potential and interaction of the calcium on these derivatives were also investigated. These derivatives decreased the action potential without altering the resting membrane potential and when antagonized with calcium, sciatic nerve action potential was decreased. Procaine and idocaine also showed the same results.