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The P2X antagonist PPADS attenuates renal sympathetic nerve activity in response to static contraction and tendon stretch
Author(s) -
Kindig Angela E.,
Hayes Shawn G.,
Kaufman Marc P.
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.21.5.a567-c
Subject(s) - ppads , sympathetic nervous system , contraction (grammar) , medicine , vasoconstriction , mean arterial pressure , muscle contraction , cats , microneurography , blood pressure , endocrinology , anesthesia , antagonist , anatomy , heart rate , receptor , baroreflex
During static exercise, mean arterial pressure (MAP) increases to provide the working muscles with oxygenated blood. The increase in MAP is mostly achieved by activation of the sympathetic nervous system, which results in vasoconstriction of peripheral vascular beds. In previous studies we have shown that pyridoxal phosphate‐6‐azophenyl‐2′, 4′‐disulfonic acid (PPADS), a P2 antagonist, reduces the firing of group III and IV afferents in response to static contraction and tendon stretch in decerebrated cats. We sought to extend these results to sympathetic nervous system activation by recording from renal sympathetic efferents. Specifically, in four cats, the % change in renal sympathetic nerve activity (RSNA) increased 55 ± 27% in response to static contraction, while the MAP increased from 138 ± 9.7 to 163 ± 14.5 mmHg. After popliteal arterial injection of PPADS, RSNA only increased 21 ± 14%, while MAP increased from 90 ± 8.7 to 111 ± 27.7 mmHg in response to contraction. Similarly, in response to tendon stretch, RSNA increased 68 ± 53%, while MAP increased from 123 ± 6.9 to 151 ± 4.5 mmHg. After injection of PPADS, however, RSNA only increased 17 ± 10%, while MAP increased from 95 ± 7.9 to 122 ± 14.9 mmHg in response to tendon stretch. There were no significant differences in the tension time indices for either contraction or stretch. These data, albeit preliminary, suggest that P2X receptors play a significant role in the activation and/or transmission of sympathetic nervous activity.