Regulation of renal artery smooth muscle tone by α 1 -adrenoceptors: role of voltage-gated calcium channels and intracellular calcium stores

2000 ◽  
Vol 28 (2) ◽  
pp. 122-127 ◽  
Author(s):  
R. E. Eckert ◽  
A. J. Karsten ◽  
J. Utz ◽  
M. Ziegler
Keyword(s):  
Smooth Muscle ◽  
Calcium Channels ◽  
Renal Artery ◽  
Intracellular Calcium ◽  
Muscle Tone ◽  
Calcium Stores ◽  
Voltage Gated ◽  
Smooth Muscle Tone ◽  
Voltage Gated Calcium Channels

scholarly journals Inhibitory Effect of Somatostatin-14 on L-Type Voltage-Gated Calcium Channels in Cultured Cone Photoreceptors Requires Intracellular Calcium

2009 ◽  
Vol 102 (3) ◽  
pp. 1801-1810 ◽  
Author(s):  
Kuihuan Jian ◽  
Rola Barhoumi ◽  
Michael L. Ko ◽  
Gladys Y.-P. Ko
Keyword(s):  
Calcium Channels ◽  
Intracellular Calcium ◽  
G Protein ◽  
Inhibitory Effect ◽  
Calcium Stores ◽  
Dependent Effect ◽  
Voltage Gated ◽  
Circadian Phase ◽  
Voltage Gated Calcium Channels ◽  
Somatostatin 14

The inhibitory effects of somatostatin have been well documented for many physiological processes. The action of somatostatin is through G-protein-coupled receptor-mediated second-messenger signaling, which in turn affects other downstream targets including ion channels. In the retina, somatostatin is released from a specific class of amacrine cells. Here we report that there was a circadian phase-dependent effect of somatostatin-14 (SS14) on the L-type voltage-gated calcium channels (L-VGCCs) in cultured chicken cone photoreceptors, and our study reveals that this process is dependent on intracellular calcium stores. Application of 500 nM SS14 for 2 h caused a decrease in L-VGCC currents only during the subjective night but not the subjective day. We then explored the cellular mechanisms underlying the circadian phase-dependent effect of SS14. The inhibitory effect of SS14 on L-VGCCs was mediated through the pertussis-toxin-sensitive G-protein-dependent somatostatin receptor 2 (sst2). Activation of sst2 by SS14 further activated downstream signaling involving phospholipase C and intracellular calcium stores. Mobilization of intracellular Ca2+ was required for somatostatin induced inhibition of photoreceptor L-VGCCs, suggesting that somatostatin plays an important role in the modulation of photoreceptor physiology.

Glutamatergic Calcium Responses in the Developing Lateral Superior Olive: Receptor Types and Their Specific Activation by Synaptic Activity Patterns

2003 ◽  
Vol 90 (4) ◽  
pp. 2581-2591 ◽  
Author(s):  
F. Aura Ene ◽  
Paul H. M. Kullmann ◽  
Deda C. Gillespie ◽  
Karl Kandler
Keyword(s):  
Calcium Channels ◽  
Intracellular Calcium ◽  
Glutamate Receptors ◽  
Cochlear Nucleus ◽  
Metabotropic Glutamate Receptors ◽  
Lateral Superior Olive ◽  
Voltage Gated ◽  
Superior Olive ◽  
Metabotropic Glutamate ◽  
Voltage Gated Calcium Channels

The lateral superior olive (LSO) is a binaural auditory brain stem nucleus that plays a central role in sound localization. Survival and maturation of developing LSO neurons critically depend on intracellular calcium signaling. Here we investigated the mechanisms by which glutamatergic afferents from the cochlear nucleus increase intracellular calcium concentration in LSO neurons. Using fura-2 calcium imaging in slices prepared from neonatal mice, we found that cochlear nucleus afferents can activate all major classes of ionotropic and metabotropic glutamate receptors, each of which contributes to an increase in intracellular calcium. The specific activation of different glutamate receptor classes was dependent on response amplitudes and afferent stimulus patterns. Low-amplitude responses elicited by single stimuli were entirely mediated by calcium-impermeable AMPA/kainate receptors that activated voltage-gated calcium channels. Larger-amplitude responses elicited by either single stimuli or stimulus trains resulted in additional calcium influx through N-methyl-d-aspartate receptors. Finally, high-frequency stimulation also recruited group I and group II metabotropic glutamate receptors, both of which mobilized intracellular calcium. This calcium release in turn activated a strong influx of extracellular calcium through a membrane calcium channel that is distinct from voltage-gated calcium channels. Together, these results indicate that before hearing onset, distinct patterns of afferent activity generate qualitatively distinct types of calcium responses, which likely serve in guiding different aspects of LSO development.

scholarly journals Role of voltage-gated calcium channels in epilepsy

2009 ◽  
Vol 460 (2) ◽  
pp. 395-403 ◽  
Author(s):  
Gerald W. Zamponi ◽  
Philippe Lory ◽  
Edward Perez-Reyes
Keyword(s):  
Calcium Channels ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels
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