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TRPC3 properties of a native constitutively active Ca2+‐permeable cation channel in rabbit ear artery myocytes
Author(s) -
Albert Anthony Paul,
Pucovsky Vladomir,
Prestwich Sally,
Large William
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.a548
Subject(s) - trpc3 , trpc1 , trpc , transient receptor potential channel , biophysics , chemistry , myocyte , ion channel , orai1 , trpc5 , patch clamp , vascular smooth muscle , microbiology and biotechnology , stim1 , biochemistry , endocrinology , biology , receptor , membrane , smooth muscle
We have previously shown a constitutively active and noradrenaline‐evoked Ca 2+ ‐permeable cation channel in rabbit ear artery myocytes which is proposed to have an important role is setting resting membrane conductance and increasing excitability of vascular tissue. In the present work we compared the properties of these native constitutively active cation channels with known properties of canonical transient receptor potential (TRPC) cation channel proteins at the single channel level using freshly dispersed rabbit ear artery myocytes and patch clamp techniques. Bath application of two anti‐TRPC3 antibodies raised against distinct epitopes on the TRPC3 channel protein markedly reduced constitutive channel activity in inside‐out patches whereas antibodies raised TRPC1,4,5,6 and 7 channel proteins had no effect on channel activity. Moreover in control experiments bath application of anti‐TRPC3 antibodies preincubated with its antigenic peptide also had no effect on channel activity. Bath application of flufenamic acid, Gd 3+ , La 3+ and Ca 2+ inhibited spontaneous channel activity in outside‐out patches with IC 50 values similar to those previous described for expressed TRPC3 channel proteins in cell lines. In addition immunocytochemical studies combined with confocal microscopy showed expression of TRPC3 channel proteins at, or close to, the plasma membrane. These data provide strong evidence that the native constitutively active cation channels in rabbit ear artery myocytes have similar properties to TRPC3 cation channel proteins and indicate that these proteins may have an important role in mediating this conductance.