Calcium signal transmission

The influx of Ca(Il) across the presynaptic membrane is essential for nerve signal transmission involving excitation by acetylcholine (26). Calcium is important in transducing regulatory signals across many membranes and is an important secondary messenger hormone. The increase in intracellular Ca(Il) levels can result from either active transport of Ca(Il) across the membrane via an import channel or by release of Ca(Il) from reticulum stores within the cell. More than 30 different proteins have been linked to regulation by the calcium complex with calmoduhn (27,28). 

Mansergh F, Orton NC, Vessey JP, Lalonde MR, Stell WK, Tremblay F, Barnes S, Rancourt DE, Bech-Hansen NT (2005) Mutation of the calcium channel gene Cacnalf disrupts calcium signaling, synaptic transmission and cellular organization in mouse retina. Hum Mol Genet 14 3035 16... 

DIRECT CALCIUM COMPOUNDS Parenteral calcium administration may 1 the positive inotropic effects of epinephrine and dobutamine Uncertain postulated that calcium modulates the signal transmission from the receptor Monitor BP closely watch for poor response to these inotropes... 

This membrane fusion process (outside the brain) is known to involve thousands of single membrane units, previously thought of as vesicles, assembled into units that have been termed "boutons". We have examined the EM texture of the boutons and found that they are in fact a cubic phase. The synaptic signal transmission can take place as frequently as hundreds of times per second. A fusion process involving a hyperbolic membrane can be well controlled, and the calcium ion influx - which induces fusion - is expected to change the conformation of the cubosome surface membrane from its planar bilayer conformation to the fusogenic saddle-saddle conformation. (It is known phase transitions of membrane lipids can occur when exposed to calcium, e.g. [40]). 

CAN YOU ANSWER THIS Other ions, including calcium and magnesium, are also important to nerve signal transmission. Arrange these Jour ions in order of increasing size K, Na, Mg, and Ccr. ... 

As the main structural material for bones and teeth, caldnm is the most abundant mineral in the body. Calcium also plays an important role in nerve signal transmission and in blood clotting. If blood calcium levels get too low, calcium stored in bones will release into the blood causing loss of bone mass. Persistently low blood calcium levels result in osteoporosis, a condition in which bones become weakened by calcium loss. The adult DRI for calcium is 1000 mg/day. Adolescents and older adults need a bit more. One cup of milk contains approximately one-third of the adult DRI. Other calcium-rich foods include cheese, sardines, oysters, and broccoli. 

In this chapter, we provide a brief overview of voltage-gated calcium channel subtypes and function, with an emphasis on neuronal transmission. The structure and kinetics of calcium channels is an extensive field of study, and outstanding reviews have recently appeared [3,4]. This chapter is focused on the potential opportunities for small-molecule intervention in neuronal signaling via antagonism of voltage-gated calcium channel subtypes, with a brief review of the chemotypes that have been recently reported to modify channel function. 

The CNS contains a substantial amount of nitric oxide synthase (NOS), which is found within certain classes of neurons. This neuronal NOS is an enzyme activated by calcium-calmodulin, and activation of NMDA receptors, which increases intracellular calcium, results in the generation of nitric oxide. Although a physiologic role for nitric oxide has been clearly established for vascular smooth muscle, its role in synaptic transmission and synaptic plasticity remains controversial. Perhaps the strongest case for a role of nitric oxide in neuronal signaling in the CNS is for long-term depression of synaptic transmission in the cerebellum. 

Calcium channels are a third major group of cation-selective channels.514 As pointed out in Box 6-D, calcium ions are involved in a very wide range of signaling functions. These are discussed in several places in this book. Several of these functions depend upon voltage-gated Ca2+ channels. Muscle is rich in L-type or DHP-sensitive channels (Box 6-D) which play a role in transmission of nerve impulses to muscles by allowing rapid flow of calcium ions into cells from outside.515... 

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