The mode of action of phenobarbital on the excitable membrane of the node of Ranvier

European Journal of Pharmacology
J R Schwarz

Abstract

Single myelinated nerve fibres of Rana esculenta were investigated under current and potential clamp conditions at 20 degrees C. Under 2.5 mM phenobarbital, the amplitude of the action potential was reversibly reduced to 85.5 +/- 5% (n = 6), and the threshold potential was raised by 32% of the control in Ringer solution. The resting potential remained constant. Solutions with 2.5 mM phenobarbital caused a decrease of the Na current to 38.3 +/- 5.6% (n = 10), when the fibre had its holding potential before the test step. The effect was reversible at wash out of the drug. The Na currents were only negligibly decreased (7 +/- 4.5%; n = 10) when the test pulse was preceded by a long lasting negative polarization to Em = -140 mV. The effect of the conditioning polarization could be described by two time constants, tau 1 = 7.1 +/- 2.0 msec and tau 2 = 44.5 +/- 9.5 msec (n = 5). Experiments with 500 msec conditioning pulses showed that the Na inactivation curve, h infinity(Em), was shifted in a negative direction along the potential axis. In the range between 0.5 and 5.0 mM phenobarbital there was a shift of 8 mV for an e-fold change in drug concentration. 15 mM Ca2+ caused a shift to the h infinity(Em) curve in a positive direction a...Continue Reading

References

Apr 1, 1977·The Journal of General Physiology·B Hille
Jun 10, 1975·Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences·B HilleB I Shapiro
Feb 1, 1977·Canadian Journal of Physiology and Pharmacology·R S Neuman, G B Frank
Aug 1, 1977·European Journal of Pharmacology·J R Schwarz, W Vogel
Jun 29, 1976·Pflügers Archiv : European journal of physiology·H H Wagner, W Ulbricht
Nov 1, 1969·The Journal of Pharmacy and Pharmacology·P KruppG Suarez-Kurtz
Jun 1, 1974·Canadian Journal of Physiology and Pharmacology·P SeemanA Staiman
Jan 1, 1974·Pflügers Archiv : European journal of physiology·W Vogel
Jan 1, 1969·Journal of Neurobiology·T NarahashiR N Poston
Feb 1, 1968·The Journal of General Physiology·B Hille
Jan 1, 1969·Pflügers Archiv : European journal of physiology·W Nonner

Citations

Mar 18, 1983·European Journal of Pharmacology·K R Courtney, E F Etter
Jun 17, 1983·European Journal of Pharmacology·J R Schwarz, R P Spielmann
Jul 21, 1992·European Journal of Pharmacology·F VeintemillaP Arhem
Jan 1, 1982·Epilepsia·R L Macdonald, M J McLean
Jan 1, 1981·Acta Physiologica Scandinavica·P Arhem, H Kristbjarnarson
Jan 1, 1983·British Journal of Pharmacology·M R CarratúD Mitolo-Chieppa
Apr 1, 1997·The Journal of Pharmacy and Pharmacology·J M Midgley, J B Stenlake

Related Concepts

Nerve Impulses
Metazoa
Salientia
Calcium
Plasma Membrane
Electrophysiology (Science)
Hydrogen-Ion Concentration
Ion Channel
Resting Potentials
Luminal

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Synthetic Genetic Array Analysis

Synthetic genetic arrays allow the systematic examination of genetic interactions. Here is the latest research focusing on synthetic genetic arrays and their analyses.

Congenital Hyperinsulinism

Congenital hyperinsulinism is caused by genetic mutations resulting in excess insulin secretion from beta cells of the pancreas. Here is the latest research.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Epigenetic Memory

Epigenetic memory refers to the heritable genetic changes that are not explained by the DNA sequence. Find the latest research on epigenetic memory here.

Cell Atlas of the Human Eye

Constructing a cell atlas of the human eye will require transcriptomic and histologic analysis over the lifespan. This understanding will aid in the study of development and disease. Find the latest research pertaining to the Cell Atlas of the Human Eye here.

Femoral Neoplasms

Femoral Neoplasms are bone tumors that arise in the femur. Discover the latest research on femoral neoplasms here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.