Effects of the tertiary amines, procaine and lidocaine, its quaternary derivative QX—314, and neutral benzocaine, on Na currents in internally perfused neuro-blastoma cells were studied using the suction-pipette voltage clamp technique (Kostyuk et al. 1975 ; Zubov et al. 1980). Neuroblastoma cells used were N18 A-l and NTR-1 subclones derived from C1300 line (Konobasova et al. 1981) and Neuro 2...

This study was undertaken to characterize pharmacologically the negative chronotropic and antiarrhythmic action of atropine and other tropane analogues. Insight into the site of action of these drugs was obtained by comparing the effects on isolated heart preparations. Dose-response curves were constructed for the negative chronotropic action on the cat Langendorff preparation and refractory pe...

The alkaloid neurotoxins aconitine, veratridine, grayanotoxin, and batrachotoxin activate the action potential Na+ ionophore by interaction with a common binding site. Concentration-response curves are fit by simple Langmuir isotherms. The fraction of Na+ ionophores activated at saturating concentrations of neurotoxin are: aconitine, 0.02; veratridine, 0.08; grayanotoxin, 0.51; and batrachotoxi...

INTRODUCTION AND OBJECTIVE To study the action of adenosine in experimental ventricular tachycardia. MATERIAL AND METHOD We studied 173 mongrel dogs weighing 13-17 kg anesthetized with 30 mg/kg sodium pentobarbital given intravenously. Myocardial lesions were provoked with the injection of 1-1.5 mL phenol in the free wall of the left ventricle. Ventricular arrhythmia was induced 30 min later ...

Andrographolide has a protective effect on the cardiovascular system. To study its cardic-electrophysiological effects, action potentials and voltage-gated Na+ (INa), Ca2+ (ICaL), and K+ (IK1, IKr, Ito and IKur) currents were recorded using whole-cell patch clamp and current clamp techniques. Additionally, the effects of andrographolide on aconitine-induced arrhythmias were assessed on electroc...

Venom of the scorpion Leiurus quinquestriatus acts cooperatively with the alkaloids veratridine, aconitine, and batrachotoxin in activating the action potential Na+ ionophore. A small (Mr = 6700), basic (pI approximately 9.8), toxic polypeptide purified approximately 80-fold from this venom by ion exchange chromatography appears homogeneous by gel electrophoresis and isoelectric focusing and, l...

The electrical signals of neurons are fundamentally dependent on voltage-gated sodium channels (VGSCs), which are responsible for the rising phase of the action potential. An array of naturally occurring and synthetic neurotoxins have been identified that modify the gating properties of VGSCs. Using murine neocortical neurons in primary culture, we have compared the ability of VGSC gating modif...

Swetha P. Karturi, MD, Hjalti Gudmundsson, MD, Masood Akhtar, MD, Arshad Jahangir, MD, Indrajit Choudhuri, MD From the Gundersen-Lutheran Health, La Crosse, Wisconsin, Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke’s Medical Centers, University of Wisconsin School of Medicine and Public Health, Milwaukee, Wisconsin, and Center for Integrative Research on Cardiovascular Aging (CIRC...