Tyrosine kinase-dependent modulation of calcium entry in rabbit colonic muscularis mucosae

• DOI: 10.1152/ajpcell.1996.270.6.c1780
• Publication Date: 2017-12-24T18:30:10Z
• Authors: N. Hatakeyama; D. Mukhopadhyay; R. K. Goyal; H. I. Akbarali
• Keywords: 0301 basic medicine; Patch-Clamp Techniques; Nifedipine; Colon; Electric Conductivity; Proteins; Muscle, Smooth; Protein-Tyrosine Kinases; 03 medical and health sciences; Animals; Calcium; Rabbits; Phosphorylation

We studied the role of tyrosine kinase in regulation Ca2+ entry single smooth muscle cells rabbit colonic muscularis mucosae using whole cell patch-clamp technique. Step depolarization to +10 mV from a holding potential -60 produced inward currents that were abolished by 1 microM nifedipine, consistent with activation L-type channels. The inhibitors, genistein and tyrphostin B42, dose dependently inhibited these currents. inactive analogue tyrphostins, A1, did not affect at concentrations up 100 microM. Conversely, phosphatase inhibitor, orthovanadate, enhanced peak 30%. Spontaneous transient outward (STOCs) (50-600 pA) elicited high K+ pipette 0-mV potential. STOCs activated due release intracellular stores, required presence extracellular concentration, insensitive nifedipine. Genistein STOCs; however, its presence, caffeine or carbachol affected. refilling stores was first depleting Ca(2+)-free media followed reperfusing Ca(2+)-containing solution for 3-5 min. Under conditions, second application evoked an current release. However, this effect when carried out genistein. Carbachol-evoked attenuated examined orthovanadate. Epidermal growth factor (200 ng/ml) 60% markedly increased over 200%. Western blot analysis, anti-phosphotyrosine antibody, showed phosphorylated protein 60 kDa control conditions. This after treatment epidermal carbachol. These results suggest 1) modulates through channels nifedipine-resistant pathways involved 2) stimulation agonists enhances mucosae.