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Modulation of ATP release in gastrocnemius muscle 1A arterioles
Author(s) -
Kluess Heidi A,
Stone Audrey J,
Evanson Kirk W
Publication year - 2010
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.24.1_supplement.985.4
Subject(s) - stimulation , receptor , arteriole , adenosine triphosphate , chemistry , gastrocnemius muscle , medicine , endocrinology , skeletal muscle , biophysics , anatomy , biology , microcirculation , biochemistry
The purpose of this study was to determine the possible sources of ATP in the synapse of 1A arterioles and to evaluate the role of α 2 ‐pre‐junctional receptors in ATP modulation. Using F344 rats (6 months old), the gastrocnemius 1A arterioles from the red gastrocnemius muscle were dissected and cannulated with glass pipettes in a tissue bath. The ATP and null probes were positioned such that the tips of the probes were touching the arteriole in similar anatomical locations and a normal ATP curve was generated (0.78μM to 25 μM ATP). The arterioles (n=3) were then field stimulated at 60Hz (200 impulses, 9mA) which resulted in ATP production of 0.54±0.76uM. This was abolished by tetrodotoxin (10uM). In a separate group of rats (n=6), the first 20 sec following 60Hz stimulation resulted in 5.1±6uM ATP production, the last 30 seconds resulted in 6.5±15.5uM ATP production. Adding the α 2 ‐agonist, UK14,304, resulted in 7.7±7.8uM ATP in the first 20 sec and 14.7±26.0uM ATP in the last 30 seconds. Blocking α 2 ‐receptors using idozoxan, resulted in an increase in ATP in the first 20 seconds (12.1±20.3uM ATP), but no change in the last 30 seconds (15.9±14.4uM ATP). These data suggest that the primary source of ATP in skeletal muscle arterioles is from the sympathetic nerve. Activation of pre‐junctional α 2 ‐receptors increases late ATP release, but blocking α 2 ‐receptors appears to increase early ATP release. This research was supported by the Arkansas Biosciences Institute and the National Institute on Aging.