We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Electrophysiologically distinct smooth muscle cell subtypes in rat conduit and resistance pulmonary arteries.
- Authors
Smirnov, Sergey V.; Beck, Richard; Tammaro, Paolo; Ishii, Tetsuro; Aaronson, Philip I.
- Abstract
Pulmonary arteries (PAs), particularly those of the rat, demonstrate a prominent voltage-gated K+ (Kv) current ( I kv), which plays an important role in the regulation of the resting potential. No detailed characterization of electrophysiological and pharmacological properties of I kv, particularly in resistance PA myocytes (PAMs), has been performed. The aim of the present study was therefore to compare I kv in rat conduit and resistance PAMs using the standard patch clamp technique. We found that 67 % of conduit PAMs demonstrated a large, rapidly activating I kv which was potently blocked by 4-aminopyridine (4-AP; IC50, 232 μ m), but was almost insensitive to TEA (18 % block at 20 m m). Thirty-three percent of cells exhibited a smaller, more slowly activating I kv which was TEA sensitive (IC50, 2.6 m m) but relatively insensitive to 4-AP (37 % block at 20 m m). These currents (termed I kv1 and I kv2, respectively) inactivated over different ranges of potential ( V0.5=−20.2 vs. -39.1 mV, respectively). All resistance PAMs demonstrated a large, rapidly activating and TEA-insensitive K+ current resembling I kv1 (termed I kv r), but differing significantly from it with respect to 4-AP sensitivity (IC50, 352 μ m), activation rate, and inactivation potential range ( V0.5, −27.4 mV). Thus, cells from conduit PAMs fall into two populations with respect to functional I kv expression, while resistance arteries uniformly demonstrate a third type of I kv. Comparison of the properties of the native I kv with those of cloned Kv channel currents suggest that I kv1 and I kv r are likely to be mediated by Kv1.5-containing homo/heteromultimers, while I kv2 involves a Kv2.1 α-subunit.
- Publication
Journal of Physiology, 2002, Vol 538, Issue 3, p867
- ISSN
0022-3751
- Publication type
Article
- DOI
10.1113/jphysiol.2001.013003