Caffeine

CAFFEINE

Proteins play important roles in inter-neuronal communication. Receptor sites are make up of proteins and the ion channels in the cell membranes are proteins. The involvement between the receptor sites and the protein channels sometimes is the guanine nucleotide-binding proteins GDP, GTP, violate know as G Protein. G proteins are heterotrimic substances, quiet of three subunits: G? ( of import), G? (beta), G? (gamma).
A receptor helping the opening of ion channels via a G protein is known as a G Protein coupled receptor. It converts external signals into an intracellular second messenger clay. In the simple second messenger system, a neurotransmitter binds on to a receptor, the G Protein binds to the receptor and becomes activated, and the alpha unit binds GTP instead of GDP and releases the other subunits. The alpha subunit then attaches to the protein ion channel and causes it to open, allowing ion flow. The G Protein in this case does non activate the protein channels in the membrane itself, but initiates a number of events which leads to the opening of the protein channels.




In the second messenger system a ligand binds to a receptor, G Protein binds to the receptor, the GDP bound to the alpha unit is replaced by GTP, causing the unit to separate multifariousness the rest of the G Protein then instead of binding to a protein channel, the alpha unit binds to another membrane protein, adenylyl cyclase. Adenylyl cyclase is responsible for converting adenosine triphosphate (ATP) to cyclic adenosine monophosphate ( camping site). Once the alpha unit latches on to adenylyl cyclase, this process is activated) .The cAMP then proceeds to activate yet another protein in the neuron, protein kinease.
Chemically, caffeine is 1,3,7, trimethylxanthine. The effects of this group of chemicals include stimulation of the rally nervous system systema nervosum centrale, diuresis, stimulation of cardiac muscle. Caffeine stimulates the CNS at the level of the cerebral cortex and medulla runner and only later...If you want to get a full essay, put up it on our website: Orderessay



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