The whole-cell patch-clamp technique was used to record Ba2+ currents through voltage-activated calcium channels in the clonal dorsal root ganglion cell line F11-B9. The pain-producing peptide bradykinin (BK; 100 nM) reduced the sustained Ba2+ current in F11-B9 cells by 30%. In cultures prelabeled with 3H-arachidonic acid and tested under ionic conditions similar to those used for recording Ba2...

The 2-phenylaminopyrimidine derivative imatinib-mesylate, a powerful protein tyrosine kinase (PTK) inhibitor that targets abl, c-kit, and the platelet-derived growth factor receptors, is rapidly gaining a relevant role in the treatment of several types of neoplasms. Because first generation PTK inhibitors affect the activity of a large number of voltage-dependent ion channels, the present study...

We have studied the current-carrying ability and blocking action of various divalent cations in the Ca channel of Lymnaea stagnalis neurons. Changing the concentration or species of the permeant divalent cation shifts the voltage dependence of activation of the Ca channel current in a manner that is consistent with the action of the divalent cation on an external surface potential. Increasing t...

This study examined whether inward rectifying K+ (KIR) channels facilitate cell-to-cell communication along skeletal muscle resistance arteries. With the use of feed arteries from the hamster retractor muscle, experiments examined whether KIR channels were functionally expressed and whether channel blockade attenuated the conduction of acetylcholine-induced vasodilation, an index of cell-to-cel...

The role of K+ channels in bile acid-independent bile flow (BAIF) was studied in the isolated and bile duct-cannulated perfused rat liver by changing the driving force on K+and by using a variety of K+channel blockers. Bile flow rate, effluent perfusate K+ content, and portal pressure were measured. Increase in perfusate K+ from 5.9 to 80 mM caused inhibition of bile flow that could be fitted t...

Addition of BaCl2 to the solution bathing colons of normal lizards did not alter the absorptive Na+ flux, but did reverse the net absorption of Cl- to become net secretion. Cl- secretion resulted from an increase in its serosal-to-mucosal movement and was positively correlated to an increase in short-circuit current. Ba2+-induced short-circuit current was dependent on the presence of both Na+ a...

Allosteric modulation of membrane receptors is a widespread mechanism by which endogenous and exogenous agents regulate receptor function. For example, several members of the nicotinic receptor family are modulated by physiological concentrations of extracellular calcium ions. In this paper, we examined conformational changes underlying this modulation and compare these with changes evoked by A...

Intracellular recordings from guinea pig trigeminal motoneurons (TMNs) in brain stem slices were used to determine the underlying ionic mechanisms responsible for our previously demonstrated enhancement of TMN excitability during jaw movements by serotonin (5-HT). 5-HT (0.5-100 microM) depolarized motoneurons and increased input resistance in the majority of neurons tested. Additionally, 5-HT r...

Whole-cell Ca2+ channel currents in rabbit portal vein cells were recorded using the amphotericin B-perforated patch-clamp technique at 35 degrees C. This technique allowed recording of stable inward currents in the absence of run-down for more than 30 minutes. Depolarizing voltage steps from a holding potential of -70 mV elicited voltage-dependent inward currents. The voltage dependence of inw...