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Exercise alone limits reductions in intimal smooth muscle K + current in a swine model of coronary artery disease
Author(s) -
Tharp Darla L.,
Ivey Jan R.,
Bowles Doug K.
Publication year - 2012
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.26.1_supplement.1138.14
Subject(s) - sed , iberiotoxin , medicine , coronary artery disease , cardiology , chemistry , endocrinology , smooth muscle
We previously demonstrated in Rapacz familial hypercholesterolemic (FH) swine with coronary artery disease that exercise (EX) combined with a low fat diet attenuated reductions in intimal coronary smooth muscle (iCSM) whole cell K + current. The goal of the present study was to determine if EX alone is sufficient in attenuating these reductions and to identify the K + channels responsible. FH swine were placed on a high fat diet at 14 months of age and then were treadmill trained (EX; n=5) or remained sedentary (SED; n=6) from 20 to 24 months of age. iCSM whole cell K + current was measured in the presence and absence of blockers for voltage‐gated (K v ; 4‐AP, 2mM), large‐conductance (BK; Iberiotoxin, IBTX, 100nM) and intermediate‐conductance Ca 2+ activated K + (IK; TRAM‐34, 100nM) channels from −70 to +100 mV. Compared to weight matched non‐FH control swine (84.3 ± 9.3 pA/pF, n=20), FH SED had reduced peak (+100 mV) whole cell K + current (14.3 ± 2.1, n=33), which was attenuated by EX (32.3 ± 4.6, n=42; p<0.001). SED (0.10 ± 0.29, n=30) had reduced K v current compared to EX (1.72 ± 0.74, n=20; +30 mV; p=0.02). BK current was not different between groups [SED (6.0 ± 1.6, n=24) vs. EX (12.5 ± 5.4, n=17); p=0.19]. Neither SED nor EX had measurable IK current. In conclusion, EX alone attenuated reductions in iCSM K + current in FH swine, in part via the maintenance of K v current. NIH HL52490