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Norepinephrine and ATP are released differentially from sympathetic nerves in rat mesenteric arteries
Author(s) -
Rhee Albert Y,
Wier Withrow Gil
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1242-c
Subject(s) - purinergic receptor , excitatory postsynaptic potential , mesenteric arteries , chemistry , norepinephrine , biophysics , electrophysiology , adrenergic , medicine , inhibitory postsynaptic potential , endocrinology , neuroscience , anatomy , artery , biology , receptor , dopamine
Sympathetic neurogenic contractions of small arteries are typically biphasic, with the initial, transient component being dependent primarily on neurally released ATP and purinergic receptors (P2X 1 ), and the latter sustained component being dependent on norepinephrine (NE) and α 1 ‐adrenoreceptors (α 1 ‐AR). Here, we sought to determine if the different time courses of the purinergic and adrenergic contractions are related to differences in the time course of neural release of ATP and NE. We used carbon fiber microelectrodes (CFE’s) and constant voltage amperometry to measure NE at the adventitial surface of rat mesenteric small arteries. Glass microelectrodes (~ 100 MOhms) were used to record ATP‐activated excitatory junction potentials (EJPs). The perivascular sympathetic nerves were stimulated using a suction electrode positioned on one end of the artery. Brief (10s) trains of stimuli (duration, 0.15ms; voltage, 20V) at relatively low frequencies (0.5 Hz) elicited TTX‐sensitive NE oxidation currents (NEOCs) and EJPS. The key observation is that the first NEOC of the train (upper trace) was always relatively large, compared to those that followed, while the first EJP (lower trace) was always relatively small. Thus, synaptic release of NE and ATP is controlled differently. This may allow for the different time courses of the purinergic and adrenergic component of neurogenic contraction. HL07309.