Details

Autor(en) / Beteiligte

• Kennedy, C.
• Todorov, L.D.
• Mihaylova-Todorova, S.
• Sneddon, P.

Titel

Release of soluble nucleotidases: a novel mechanism for neurotransmitter inactivation?

Ist Teil von

• Trends in pharmacological sciences (Regular ed.), 1997-08, Vol.18 (8), p.263-266

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

1997

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• When nonpeptide neurotransmitters are released from nerves, their actions are limited temporally by removal from the extracellular space via one of two active processes. For amines and amino acids, specific, high-affinity transporters mediate their uptake back into the nerves or into surrounding support cells. In contrast, acetylcholine and adenosine 5'-triphosphate (ATP) are broken down by extracellular enzymes. Acetylcholine is inactivated by acetylcholinesterase in the synaptic cleft and then choline is taken up into the nerve. Extracellular membrane-bound nucleotidases (ectonucleotidases) which sequentially dephosphorylate ATP to adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP) and adenosine are present in most tissues and it is generally assumed that these enzymes terminate the neurotransmitter actions of ATP in the brain and periphery. However, it was recently found that when the sympathetic nerves innervating the guinea-pig vas deferens are stimulated, they release not only neuronal ATP, but also soluble nucleotidases which break down ATP to adenosine. This release of specific nucleotidases may represent a novel mechanism for terminating the actions of a neurotransmitter.