Voltage-activated Ca2+ channels in rat renal afferent and efferent myocytes: no evidence for the T-type Ca2+ current
| Autor: | Sergey V. Smirnov, Rodger Loutzenhiser, Kathy Loutzenhiser |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Male
Efferent arteriole medicine.medical_specialty kidney Patch-Clamp Techniques Afferent arterioles renal arterioles Calcium Channels L-Type Nifedipine Physiology Efferent Scorpion Venoms Kidney Muscle Smooth Vascular patch-clamp technique Rats Sprague-Dawley Calcium Channels T-Type chemistry.chemical_compound Arteriole Physiology (medical) Internal medicine medicine.artery medicine Animals vascular smooth muscle cells Patch clamp Voltage-dependent calcium channel Chemistry renal microcirculation electrophysiology Rats smooth muscle cells Arterioles Electrophysiology Calcium channels medicine.anatomical_structure Endocrinology Biophysics Kurtoxin Cardiology and Cardiovascular Medicine |
| Zdroj: | Smirnov, S V, Loutzenhizer, K & Loutzenhiser, R 2013, ' Voltage-activated Ca 2+ channels in rat renal afferent and efferent myocytes: no evidence for the T-type Ca 2+ current ', Cardiovascular Research, vol. 97, no. 2, pp. 293-301 . https://doi.org/10.1093/cvr/cvs310 |
| DOI: | 10.1093/cvr/cvs310 |
| Popis: | AIMS: Based on indirect methods, it has been suggested that both L- and T-type Ca(2+) channels mediate signalling in the renal afferent arteriole and that T-type Ca(2+) channels are involved in signalling in the efferent arteriole. However, Ca(2+) currents have never been studied in these two vessels. Our study was initiated to directly determine the type of Ca(2+) channels in these vessels for the first time, using patch clamp. METHODS AND RESULTS: Native myocytes were obtained from individually isolated rat renal afferent and efferent arterioles and from rat tail arteries (TA). TA myocytes, which possess both L- and T-type Ca(2+) currents, served as a positive control. Inward Ca(2+) and Ba(2+) currents (I(Ca) and I(Ba)) were measured in 1.5 mmol/L Ca(2+) and 10 mmol/L Ba(2+), respectively, using the whole-cell configuration. By exploiting known differences in activation and inactivation characteristics and differing sensitivities to nifedipine and kurtoxin, the presence of both L- and T-type Ca(2+) channels in TA myocytes was readily demonstrated. Afferent arteriolar myocytes exhibited relatively large I(Ca) densities (-2.0 ± 0.2 pA/pF) in physiological Ca(2+) and the I(Ba) was 3.6-fold greater. These currents were blocked by nifedipine, but not by kurtoxin, and did not exhibit the activation and inactivation characteristics of T-type Ca(2+) channels. Efferent arteriolar myocytes did not exhibit a discernible voltage-activated I(Ca) in physiological Ca(2+). CONCLUSION: Our findings support the physiological role of L-type Ca(2+) channels in the afferent, but not efferent, arteriole, but do not support the premise that functional T-type Ca(2+) channels are present in either vessel. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|