Tonic and phasic effects of local anesthetics searched with sucrose-gap technique

ABSTRACT TONIC AND PHASIC EFFECTS OF LOCAL ANESTHETICS SEARCHED WITH SUCROSE-GAP TECHNIQUE Effects of local anesthetics on membrane and action potentials can be determined by various intracellular and extracellular recording techniques. In this study, we explored the effects of procaine and lidocaine on compound resting potential (CRP) and compound action potential (CAP) parameters (such as amplitude (V), latent period (TJ, depolarisation time (TDE), and half-repolarisation time (VaT^)) in the frog sciatic nerve bundles. We used 5-7 cm length of nerve bundles which were dissected from 70-80 g weight of frogs (Rana cameranoi). CRP and CAP parameters were recorded with sucrose-gap technique at 1, 2.1, 4.2 and 8.4 mM procaine and 1, 2.1 and 4.2 mM lidocaine concentrations. Nerve fibers were stimulated with single, tonic and frequency-dependent stimulations. We found that procaine and lidocaine reduced the amplitude of BAP and extended latent period, depolarisation time and half-repolarisation time of BAP and hyperpolarised the CRP with these concentrations at single stimulation. BAP was more reduced at 2.1 mM of procaine and lidocaine concentrations when nerve fibers were stimulated with frequency-dependent stimulations. Key Words: Compound Resting Potential, Compound Action Potential, Sucrose-Gap Technique, Procaine, Lidocaine. IX