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Unidirectional and bidirectional vasodilatory responses to single and multiple dilators
Author(s) -
Junuzovic Jasna,
Murrant Coral Lyn
Publication year - 2006
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.20.4.a276-a
Subject(s) - sodium nitroprusside , vasodilation , adenosine , contraction (grammar) , chemistry , cremaster muscle , pinacidil , nitric oxide , biophysics , medicine , endocrinology , microcirculation , biology , biochemistry , glibenclamide , diabetes mellitus
The dilatory responses to skeletal muscle contraction over time may be the product of a combination of multiple dilators (e.g. nitric oxide (NO), K ATP activation, and adenosine (ADO)) in varying concentrations. To better understand the vascular responses to dilators relevant in muscle contraction we examined hamster cremaster arteriolar dilations (max. diameter approx. 40um) in situ to micropipette application of either 10 −6 M or 10 −5 M pinacidil (PIN, a K ATP channel opener), 10 −3 M or 10 −4 M ADO, 10 −4 M or 10 −5 M sodium nitroprusside (SNP, an NO donor), or a combination of 10 −5 M PIN and 10 −4 M ADO. Arteriolar diameters were measured at the site of application (local) and at sites 500um upstream and 500um downstream. 10 −6 M PIN produced local, upstream and downstream responses (2.8±0.6, 2.1±0.5, 1.5±0.6um respectively) and each dilation was larger in response to 10 −5 M PIN (5.9±0.9, 3.8±1.3, 4.2±0.9um). 10 −4 M ADO produced local and upstream but no significant downstream dilations (4.9±0.7, 1.7±0.3, 0.4±0.3um), however, 10 −3 M ADO produced significant dilations at all three sites (16.9±2.2, 4.7±1.0, 4.2±1.2um). 10 −5 M SNP resulted in a local dilation only (10.4+2.3um) but 10 −4 M SNP produced dilations at all three sites (5.9±0.9, 3.8±1.3, 4.2±0.9um). The combination of 10 −4 M ADO and 10 −5 M PIN resulted in local, upstream and downstream dilations of 10.0±3.5, 8.8±1.6, 7.4±1.6um, but upstream and downstream responses were larger than the sum of the dilations from each dilator applied individually. Therefore, vasodilatory responses differ depending on the dilator and its concentration and the presence of other dilators. This study was supported by NSERC and PREA.