Factors affecting synaptic transmission

Several factors influence synaptic transmission of electrical impulses  

Neurons are very sensitive to changes in the pH of the interstitial fluid surrounding them. Normally, the pH of arterial blood is 7.4. Under conditions of alkalosis, in which pH increases, the excitability of neurons also increases, rendering them more likely to generate action potentials. This inappropriate stimulation of the nervous system may lead to seizures, particularly in epileptics predisposed to them. Under conditions of acidosis, in which pH decreases, the excitability of neurons is depressed, rendering them less likely to generate action potentials. This lack of nervous system stimulation may lead to a comatose state. Severe diabetic acidosis or acidosis associated with end-stage renal failure will often lead to coma. 

Neuronal function depends on a constant supply of oxygen. Hypoxia, a decrease in oxygen availability, depresses neuronal activity. Interruption of blood flow to the brain for only a few seconds leads to unconsciousness. A prolonged lack of blood flow, which is characteristic of stroke, leads to permanent brain damage in the affected area. 

Many drugs, toxins, and diseases exert their clinical effects by altering some phase of synaptic activity. These effects may occur by means of  

Altered release. Tetanus is an infectious disease caused by the bacterium Clostridium tetani. This bacterium produces a neurotoxin active on inhibitory synapses in the spinal cord. Motor neurons, which supply skeletal muscle and cause contraction, have cell bodies that lie in the spinal cord. Under normal circumstances, these motor neurons receive excitatory and inhibitory inputs from various sources. The balance of these inputs results in the appropriate degree of muscle tone or muscle contraction. Tetanus toxin prevents the release of gamma amino butyric acid (GABA), an important neurotransmitter active at these inhibitory synapses. Eliminating inhibitory inputs results in unchecked or unmodulated excitatory input to the motor neurons. The resulting uncontrolled muscle spasms initially occur in the muscles of the jaw, giving rise to the expression lockjaw. The muscle spasms eventually 

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Fluoroaluminate complexes can mimic the action of many hormones, neurotransmitters, and growth factors. G-protein-mediated cell responses are key steps in neurotransmission and intercellular signaling in the brain [20], and TFA acts as an active stimulatory species [21]. Exposure of osteoblasts to TFA results in a marked potentiation of intracellular orthophosphate transport, alluding to the anion s ability to increase bone mineralization [22]. Brief exposure to aluminum fluoride complexes induces prolonged enhancement of synaptic transmission [23] and can potentially affect the activity of many other ion channels and enzymes in the kidney [24]. Rapid and dynamic changes of the cytoskeletal actin network are of vital importance to the motility of many cells, and TFA induction effects a pronounced and sustained... 

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