High-voltage-activated (HVA) calcium channels are known to be the primary source of calcium for glucose-stimulated insulin secretion. However, few studies have investigated how these channels can be regulated by chronically elevated levels of glucose. In the present study, we determined the level of expression of the four major HVA calcium channels (N-type, P/Q-type, L(C)-type, and L(D)-type) i...

Platelet-activating factor (PAF) is an autocrine trophic/survival factor for the preimplantation embryo. PAF induced an increase in intracellular calcium concentration ([Ca2+]i) in the 2-cell embryo that had an absolute requirement for external calcium. L-type calcium channel blockers (diltiazem, verapamil, and nimodipine) significantly inhibited PAF-induced Ca2+ transients, but inhibitors of P...

Effects of haloperidol on L-type CaV1.2 channel were studied. Calcium current was measured in whole cell patch-clamp using calcium as a charge carrier. Inhibition by haloperidol was investigated in CaV1.2 channel natively expressed in rat cardiac myocytes and recombinant cardiac (CaV1.2a) and vascular (CaV1.2b) splice variants of the channel expressed in HEK 293 cells. Haloperidol inhibited L-t...

The protective effect of a L-type calcium channel blocker, nimodipine, on cell injury induced by oxygen-glucose deprivation (OGD) in PC12 cells was investigated. PC12 cells were exposed to in-vitro oxygen-glucose deprivation (30 minutes and 60 minutes respectively) in the presence or absence of nimodipine (10mM/L) in three different time schedules (pre-24h, pre-3h and concurrently). Cellular vi...

The goal of these studies was to determine if different calcium channel antagonists affect glucose transport in a neuronal cell line. For these studies, rat pheochromocytoma (PC12) cells were treated with L-, Tand N-type calcium channel antagonists prior to measuring the accumulation of H-2-deoxyglucose (H-2-DOG). The L-type channel antagonists, nimodipine, nifedipine, verapamil, and diltiazem ...

After brief periods of heightened stimulation, calcium entry through L-type calcium channels leads to activation of the transcription factor cAMP response element-binding protein (CREB) and CRE-dependent transcription. Many of the details surrounding the mechanism by which L-type calcium channels are privileged in signaling to CREB, to the exclusion of other calcium entry pathways, has remained...

The high-voltage-activated calcium channel is a multimeric protein complex containing α(1), α(2)/δ, β, and γ subunits. The α(1) subunit is the ion conduction channel and contains the binding sites for calcium channel blockers and toxins. Three genes code for distinct L-type, dihydropyridine-sensitive α(1) subunits; one gene codes for the neuronal P-type (Purkinje) α(1) subunit; and one gene cod...