Transmission, synaptic

Lead is also known to increase miniature end-plate potential frequency at the unstimulated neuromusculeir junction, indicating that Pb causes an increase in spontcmeous trcmsmitter release. These results, in contrast to the blocking effect of Pb on transmitter-stimulated release, suggest that there may be two mechanisms, one for stimulated and one for spontemeous trems-mitter release. 

The competition of Pb with Ca outside the CNS has already been discussed reseeirch has shown that Pb strongly competes with Ca at the neuronal level as well. In the cholinergic system, the effects of Pb (e.g., the blocking of stimulated ACh release) are similar to 

---

Acetylcholine serves as a neurotransmitter. Removal of acetylcholine within the time limits of the synaptic transmission is accomplished by acetylcholinesterase (AChE). The time required for hydrolysis of acetylcholine at the neuromuscular junction is less than a millisecond (turnover time is 150 ps) such that one molecule of AChE can hydrolyze 6 105 acetylcholine molecules per minute. The Km of AChE for acetylcholine is approximately 50-100 pM. AChE is one of the most efficient enzymes known. It works at a rate close to catalytic perfection where substrate diffusion becomes rate limiting. AChE is expressed in cholinergic neurons and muscle cells where it is found attached to the outer surface of the cell membrane. 

A large fraction of anticonvulsants are based on the attempt to boost inhibitory synaptic transmission in... 

One of the oldest antiepileptic drugs, bromide, has been repotted to boost inhibition by an unknown mechanism. Bromide is still in use in certain cases of tonic-clonic seizures and in pediatric patients with recurrent febrile convulsions and others. The mechanism of action may include a potentiation of GABAergic synaptic transmission, although the precise target is not known. 

Synaptic Transmission a-Adrenergic System Muscarinic Receptors Histaminergic System... 

CaM plays a key role in many cellular processes. In the CNS, it is involved in synaptic transmission and neuronal plasticity associated with short-term and longterm potentiation, and learning and memory processes. 

Cholinergic Transmission is the process of synaptic transmission which uses mainly acetylcholine as a transmitter. Cholinergic transmission is found widely in the peripheral and central nervous system, where acetylcholine acts on nicotinic and muscarinic receptors. 

The light chains of the clostridial neurotoxins are metalloproteases with exclusive specificity for neuronal SNAREs. TeNT, BoNTs B,D,F, and G cleave synapto-brevin, BoNTs A and E SNAP-25, and BoNT/Cl syntaxin, and to a lesser extent also SNAP-25. Cleavage of any of the SNAREs causes complete and irreversible block of synaptic transmission. 

Synaptic Transmission Voltage-dependent Na+ Channels Voltage dependent Ca2+ Channels Nicotinic Receptors... 

Synaptic Transmission Purtnergic System Tachykinins and their Receptors... 

Whereas the role of AMPA and NMDA receptors in fast synaptic transmission is well characterized, only few examples demonstrating synaptic responses due to kainate receptor activation are known so far. 

Nicotinic Receptors Muscle Relaxants Synaptic Transmission... 

The transporters for 5HT, noradrenaline and dopamine, biogenic monoamines, are genetically related, exist as single isoforms and are expressed on the surface of nerve cells, which use monoamines as (or convert them into) their cognate neurotransmitter. The single-isoform monoamine transporters fulfil all three fundamental functions (reuptake, limiting synaptic transmission, and control of the extracellular neurotransmitter concentration). Inactivation of DAT, NET, or SERT results in an increased extracellular lifetime and level of monoamine neurotransmitter, but decreased intracellular storage and evoked release (Fig. 3). 

Nitrergic transmission is synaptic transmission by nitric oxide. In contrast to other transmitters, NO is not preformed and stored in synaptic vesicles. When an... 

Functions of nNOS include long-term regulation of synaptic transmission in the CNS (long-term potentiation, long-term depression), whereas there is no evidence for an involvement of nNOS-derived NO in acute neurotransmission. Retrograde communication across synaptic junctions is presumed to be involved in memory... 

The first clear evidence for nerve-nerve purinergic synaptic transmission was in 1992, when it was... 

Synaptic transmission is the transfer of biological information across synapses. Drugs that influence synaptic transmission play an eminent role in therapy, for two reasons. First, the nervous system controls all tissues. Second, with few exceptions synaptic transmission is chemical, operating by means of transmitter substances, and synapses therefore provide a large number of drug targets, such as the enzymes that synthesize the transmitter. However, the importance of... 

---