ATP is released from nerve terminals and from activated muscle fibres on stimulation of the rat phrenic nerve

Abstract

Nerve stimulation increases the concentration of ATP in the synaptic cleft, which can act as a neurotransmitter or as a presynaptic neuromodulator. Using the luciferin-luciferase assay, we observed that the extracellular concentration of ATP increased by 11 -26 nM over a basal concentration of 6 nM, in a frequency dependent manner (1 -5 Hz), in the adult rat phrenic nerve-hemidiaphragm preparation. This ATP release depends on nerve activity since it was abolished by tetrodotoxin (1 mM) and is strictly dependent on the presence of extracellular calcium. However, more than half of this nerve-evoked release of ATP is derived from activated muscle fibres since the selective postsynaptic nicotinic receptor antagonist, a-bungarotoxin (1 mM), inhibited by over 60% the evoked release of ATP. The presently observed post-synaptic release of ATP together with the previously reported lack of post-synaptic effects of ATP and to the ability of ATP to act as a presynaptic modulator open the possibility that ATP may behave as a retrograde messenger at this neuromuscular junction. q

Effect of purinergic receptor activation on Na+-K+ pump activity, excitability, and function in depolarized skeletal muscle

“…In vivo, the major source of purines for the purinergic signaling cascade in active muscles is local release from nerve endings and muscles fibers causing auto-and paracrine effects (1,4,12,14,22,23,38,40,47,48). Several mechanisms by which ATP is released from cells have been proposed, including vesicular release and release though multidrug resistence protein transporters (24,50).…”

“…adenosine 5=-triphosphate disodium salt; adenosine 5=-diphosphate sodium salt; purinoceptors; M-wave; muscle contraction; phospholipase C PURINE AND PYRIMIDINE RELEASE in the extracellular environment has been observed in many tissues, including muscles where the release occurs from the nerve endings in neuromuscular junctions and from the active muscle fibers (1,4,12,14,22,23,38,40,47,48). The combination of specific receptors for purines and pyrimidines, the purinoceptors, and the rapid extracellular breakdown of the purines and pyrimidines by ectonucleotidases enables these compounds to function as finely regulated extracellular signaling molecules (1,4,48,51).…”

Basic and Applied Aspects of Color Tuning of Bioluminescence Systems

“…For example, the light intensity can correlate with the amount of ATP under excess luciferin and luciferase, resulting in a beetle bioluminescence system that can measure ATP concentration 39) and therefore, detect bacteria in food because bacteria contain ATP as an energy source. 40) There are many commercial products or kits in common use for measuring ATP and detecting bacteria.…”

TGF-β2 alters the characteristics of the neuromuscular junction by regulating presynaptic quantal size

“…If this difference in activation also occurs at the NMJ, then TGF-β2 would be expected to modulate selectively the pathways controlled by spontaneous release; such modulation might subtly regulate the postsynaptic cell. Second, cholinergic vesicles also release compounds such as ATP that have both pre-and postsynaptic targets (30,31). Hence, the relative strengths of the cholinergic and noncholinergic pathways should change when QSpre is altered unless all the contents of synaptic vesicles are coordinately regulated by TGF-β2.…”