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Pre‐junctional potentiation of ATP overflow is age‐dependent
Author(s) -
Kluess Heidi A,
Stone Audrey J,
Evanson Kirk W
Publication year - 2011
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.25.1_supplement.1026.19
Subject(s) - arteriole , receptor , medicine , long term potentiation , agonist , stimulation , chemistry , endocrinology , anatomy , circulatory system
The purpose was to evaluate the role of α 2 ‐pre‐junctional receptors in ATP overflow in the resistance arterioles from adult and middle aged rats. Using F344 rats (6 months old: n=5 female; n=6 males) and (12 months old: n=5 females; n=5 males), the 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). Field stimulation resulted in an increase in ATP overflow in arterioles from 6‐month old rats (1.88±6.14 μM ATP) and 12‐month old rats (34.95±91.30 μM ATP). Adding the α 2 ‐agonist, UK14,304, resulted in no change in 6‐month olds (3.34±3.10 μM ATP), but increased ATP overflow in some 12‐month olds (119.09±256.71 μM). Blocking α 2 ‐receptors using idozoxan, had little effect on 6‐month olds (1.81±1.59 μM ATP), but blocked the action of UK14,304 in 12‐month olds (11.74±23.04 μM ATP). There were no sex‐related differences in ATP overflow. These data indicate that there are significant age‐related changes in mechanisms modulating ATP overflow in skeletal muscle resistance vessels and that α 2 ‐pre‐junctional activation may not act in the way previously described in the heart, brain and tail. This research was supported by NIA (R03AG033245) and the Arkansas Biosciences Institute.