Lidocaine increases the number of beta-adrenoceptors in neonatal rat cardiocytes in culture

Lidocaine-induced alterations in agonist-induced ion transport of cultured swine tracheal submucosal gland cells

It has been documented that topical administration of lidocaine can cause airway complications, although it is the most used local anesthetic for laryngotracheal anesthesia. Thus, in this study we investigated the local actions of lidocaine on basal and autonomic secretagogue-induced ion transport in cultured swine tracheal submucosal gland cells. Ion transport plays an important role in maintaining effective mucociliary clearance and pulmonary defense mechanisms. It was measured as short-circuit current (Isc) utilizing Ussing chamber methodology. Exposure of cultured gland cells to lidocaine evoked a transient response with an initial increase in Isc followed by a decrease. The increase in Isc induced by lidocaine (3 mM) was 8.0 +/- 1.5 microA/cm(2). The maximal increases in Isc induced by isoproterenol and acetylcholine were 9.4 +/- 0.6 and 38.3 +/- 2.3 microA/cm(2), respectively. However, lidocaine significantly decreased the isoproterenol-induced increases in Isc. Acetylcholine-induced responses were not changed by lidocaine. Atropine did not significantly affect lidocaine-evoked events in ion transport. These results suggest that lidocaine directly alters epithelial transport of ions and also inhibits the adrenergic stimulation of epithelial ion transport.

Effect of lidocaine on alpha 1-adrenoceptors in cultured neonatal rat cardiocytes

The effect of lidocaine on alpha 1-adrenoceptors in cultured neonatal rat ventricular cardiocytes was studied by binding assay. When the cells were cultured in the presence of lidocaine, the binding of (+/-)-beta-([125I]iodo-4-hydroxyphenyl)-ethyl-aminomethyl-tetralone to the cells increased in a concentration- and time-dependent manner. The effect was due to an increase in maximum binding but not due to a change in the dissociation constant for the ligand. The increased number of alpha 1-adrenoceptors returned to the control level after culturing the cells without lidocaine. The stimulating effect on the number of alpha 1-adrenoceptors of lidocaine was also observed in the presence of norepinephrine. Other class I antiarrhythmic drugs such as procainamide. disopyramide, mexiletine and flecainide increased the number of alpha 1-adrenoceptors in the cells. These results suggest that cardiac responsiveness mediated by alpha 1-adrenoceptors is increased by class I antiarrhythmic drugs.