PURPOSE There is little known about the membrane properties of retinal pigment epithelial (RPE) cells with respect to calcium. The authors attempted to characterize membrane calcium channels from solitary fresh and cultured RPE cells from normal and dystrophic rat retinas. METHODS RPE cells were enzymatically dissociated from eyes of neonatal rats of several strains, including dystrophic RCS ...

Chen, Huanmian and Nevin A. Lambert. Inhibition of dendritic located on cell bodies, whereas R-type and low-threshold calcium influx by activation of G-protein–coupled receptors in the T-type channels are relatively abundant on dendrites (Chrishippocampus. J. Neurophysiol. 78: 3484–3488, 1997. Gi proteins tie et al. 1995; Magee and Johnston 1995). Pertussis toxininhibit voltage-gated calcium ch...

Cells use endocytotic membrane retrieval to compensate for excess surface membrane after exocytosis. Retrieval is thought to be calcium-dependent, but the source of this calcium is not known. We found that, in sea urchin eggs, endocytotic membrane retrieval required extracellular calcium. Inhibitors of P-type calcium channels-cadmium, omega-conotoxin MVIIC, omega-agatoxin IVA, and omega-agatoxi...

L-type calcium channel activity has been associated with a number of cytoplasmic responses, including gene transcription and activation of calcium-dependent enzymes, yet their direct contribution to the electrical activities of neurons has remained largely unexplored. Here we report the cloning and functional characterization of a molluscan L-type calcium channel homologue, LCa(v)1, and investi...

Voltage-dependent L-type calcium channels that permit cellular calcium influx are essential in calcium-mediated modulation of cellular signaling. Although the regulation of voltage-dependent L-type calcium channels is linked to many factors including cAMP-dependent protein kinase A (PKA) activity and actin cytoskeleton, little is known about the detailed mechanisms underlying the regulation in ...

Intracellular calcium plays a crucial role in modulating a variety of functions such as muscle contraction, hormone secretion, gene expression, or cell growth. Calcium signaling has been however shown to be more complex than initially thought. Indeed, it is confined within cell microdomains, and different calcium channels are associated with different functions, as shown by various channelopath...

Studies on the amphibian neuromuscular junction have indicated that N-type calcium channels are the sole mediators of stimulus-evoked neurotransmitter release. We show, via both presynaptic and postsynaptic voltage-clamp measurements, that dihydropyridine (DHP)-sensitive calcium channels also contribute to stimulus-evoked release at developing Xenopus neuromuscular junctions. Whereas inhibition...

INTRODUCTION WE REPORTED THAT RYANODINE RECEPTORS ARE EXPRESSED IN TWO DIFFERENT TYPES OF MAMMALIAN PERIPHERAL TASTE RECEPTOR CELLS: Type II and Type III cells. Type II cells lack voltage-gated calcium channels (VGCCs) and chemical synapses. In these cells, ryanodine receptors contribute to the taste-evoked calcium signals that are initiated by opening inositol trisphosphate receptors located o...