Abstract
Whole-cell perforated patch clamp recordings were used to analyze selectivity of omega-CgTx-MVIIC toxin for voltage-dependent calcium currents in cultured myenteric neurons from guinea-pig small intestine. Omega-CgTx-MVIIC (300 nM) blocked 37 +/- 9% of the peak current activated from -80 mV in 15 neurons by mostly affecting the plateau phase of the current. The toxin suppressed peak current activated from -30 mV dose-dependently with an IC50 of 70 +/- 8 nM. The blockade was complete at toxin concentrations of 1 microM. Thus, it appears that omega-CgTx-MVIIC blocks high voltage activated (HVA) calcium channels in the myenteric neurons unselectively as well as other types of HVA Ca2+ channels including P and Q channels.
Publication types
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Barium / metabolism
-
Calbindins
-
Calcium / metabolism*
-
Calcium Channel Blockers / pharmacology
-
Calcium Channels / physiology*
-
Calcium Channels, N-Type*
-
Electric Conductivity
-
Guinea Pigs
-
In Vitro Techniques
-
Inhibitory Concentration 50
-
Intestine, Small / cytology
-
Intestine, Small / innervation
-
Ion Channel Gating
-
Membrane Potentials
-
Myenteric Plexus / cytology*
-
Neurons / drug effects*
-
Neurons / metabolism
-
Patch-Clamp Techniques
-
Peptides / pharmacology*
-
S100 Calcium Binding Protein G / analysis
-
omega-Conotoxins*
Substances
-
Calbindins
-
Calcium Channel Blockers
-
Calcium Channels
-
Calcium Channels, N-Type
-
Peptides
-
S100 Calcium Binding Protein G
-
omega-Conotoxins
-
voltage-dependent calcium channel (P-Q type)
-
Conus magus toxin
-
Barium
-
Calcium