Learn More
Caffeine was used to study the intracellular Ca2+ pools of bovine chromaffin cells. Its effects on cytosolic Ca2+ concentration ([Ca2+]i) were examined using fura-2. Caffeine caused a transient increase in [Ca2+]i in the presence or absence of extracellular Ca2+. In the former case, the caffeine-induced [Ca2+]i increase was higher and stayed above the basal(More)
1. In cell-attached patch-clamp recordings from freshly dissociated rat caudate-putamen neurons, an 85-pS inwardly rectifying K+ channel, which was previously found to be modulated by D2-like dopamine receptors, was blocked by externally applied BaCl2 or CsCl. 2. At concentrations between 100 and 500 microM, Ba2+ blockade was voltage dependent, with a(More)
We have used cell-attached patch-clamp electrophysiology to characterize the activation and distribution of an 85 pS K+ channel on freshly dissociated rat striatal (caudate-putamen) neurons. In recordings from 643 cells, openings of this channel showed an absolute dependence on the presence of dopamine or the D2-like dopamine receptor agonist quinpirole in(More)
In single channel patch-clamp recordings from freshly dissociated rat corpus striatum (caudate-putamen) neurons, the sulfonylurea drugs tolbutamide and glibenclamide caused a concentration-dependent blockade of a K+ channel that is activated by D2 dopamine receptor agonists. Tolbutamide was about 10-100 times more potent than glibenclamide, a rank-order(More)
The presence of a Na+/Ca2+ exchanger in bovine adrenal chromaffin cells was demonstrated by measuring the efflux of 45Ca2+ which had been preloaded into cells by a brief depolarization. The efflux of 45Ca2+ was dependent on extracellular Na+ (Na+o); 45Ca2+ efflux was significantly decreased by replacing Na+o with N-methylglucamine (NMG), or Li+. Replacement(More)
BACKGROUND Mammalian spermatozoa become fully motile and fertile during transit through the luminal fluid of the epididymis. At least 200 proteins are present in the epididymal lumen, but the potential roles of these luminal proteins in male fertility are unknown. Investigation of the function of these proteins will elucidate the mechanism of sperm(More)
An 85 pS K+ channel of rat caudate-putamen neurons, which is activated by dopamine D2 receptors and inhibited by sulfonylurea drugs, was studied using cell-attached patch-clamp electrophysiology. This channel was inhibited by externally-applied U-37883A (4-morpholinecarboximidine-N-1-adamantyl-N'-cyclohexyl hydrochloride), a blocker of vascular(More)
We reported earlier that adenine nucleotides and adenosine inhibit acetylcholine-induced catecholamine secretion from bovine adrenal medulla chromaffin cells. In this article, we used an adenosine analogue, N6-L-phenylisopropyladenosine (PIA), to study the mechanism underlying inhibition of catecholamine secretion by adenosine. PIA inhibits secretion(More)
The effects of caffeine on Ca2+ fluxes and catecholamine secretion in bovine adrenal chromaffin cells were examined. Caffeine inhibited secretion. 45Ca2+ uptake and cytosolic Ca2+ concentration ([Ca2+]i) rise induced by the nicotinic receptor agonist 1.1-dimethyl- 4-phenylpiperazinium (DMPP) and the Na+ channel activator veratridine. The inhibitory effect(More)