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K V 1 channel‐mediated dilation to isoproterenol in cerebral arteries is disrupted in angiotensin II ‐induced hypertension
Author(s) -
Moore Christopher Leighton,
Nelson Piper L.,
Chandrika Bhavya B.,
Rhee Sung W.
Publication year - 2013
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.27.1_supplement.877.6
Subject(s) - vasoconstriction , vasodilation , angiotensin ii , medicine , endocrinology , electrical impedance myography , cerebral arteries , saline , chemistry , western blot , vascular smooth muscle , biology , blood pressure , biochemistry , smooth muscle , gene
We previously reported the expression of scaffolding protein, postsynaptic density‐95 (PSD95) in rat cerebral vascular smooth muscle cells (cVSMC). PSD95 binds with K V 1 channels at the plasma membrane of cVSMC to mediate vasodilation. A membrane‐permeable peptide (K V 1‐C) that competes for PSD95 binding causes vasoconstriction and blunts vasodilation induced by isoproterenol (ISO). This study explores whether angiotensin II‐induced hypertension (AHT) alters ISO‐induced vasodilation and K V 1‐C peptide response. Sprague‐Dawley rats were infused by osmotic pumps with saline or angiotensin II (500ng/kg/min) for 14 days. Blood pressure was measured by tail‐cuff plethysmography. Cerebral arteries (CA) were isolated for pressure myography and protein lysate. Western blot analysis revealed K V 1.2 subunits were downregulated by ~70% (n=5) in CA lysates from AHT rats compared to saline rats. In pressurized CA, maximal vasodilation to ISO was reduced by half in AHT rats compared to saline rats. K V 1‐C peptide treatment had little effect on CA from AHT rats but it blunted ISO response in CA from saline rats to the level of AHT rats (n=5–8). These findings suggest that a loss of K V 1 channel expression and function in CA from AHT rats may account for the blunted ISO response and that K V 1‐C peptide confers similar disruption of PSD95‐mediated K V 1 channel function in CA from saline rats.