Identification of L- and T-type Ca2+ channels in rat cerebral arteries: role in myogenic tone development
| Parent link: | American Journal of Physiology - Heart and Circulatory Physiology: Scientific Journal.— , 1997- Vol. 304, № 1.— 2013.— [14 p.] |
|---|---|
| Other Authors: | , , , , , , |
| Summary: | Title screen L-type Ca2+ channels are broadly expressed in arterial smooth muscle cells, and their voltage-dependent properties are important in tone development. Recent studies have noted that these Ca2+ channels are not singularly expressed in vascular tissue and that other subtypes are likely present. In this study, we ascertained which voltage-gated Ca2+ channels are expressed in rat cerebral arterial smooth muscle and determined their contribution to the myogenic response. mRNA analysis revealed that the ?1-subunit of L-type (Cav1.2) and T-type (Cav3.1 and Cav3.2) Ca2+ channels are present in isolated smooth muscle cells. Western blot analysis subsequently confirmed protein expression in whole arteries. With the use of patch clamp electrophysiology, nifedipine-sensitive and -insensitive Ba2+ currents were isolated and each were shown to retain electrical characteristics consistent with L- and T-type Ca2+ channels. The nifedipine-insensitive Ba2+ current was blocked by mibefradil, kurtoxin, and efonidpine, T-type Ca2+ channel inhibitors. Pressure myography revealed that L-type Ca2+ channel inhibition reduced tone at 20 and 80 mmHg, with the greatest effect at high pressure when the vessel is depolarized. In comparison, the effect of T-type Ca2+ channel blockade on myogenic tone was more limited, with their greatest effect at low pressure where vessels are hyperpolarized. Blood flow modeling revealed that the vasomotor responses induced by T-type Ca2+ blockade could alter arterial flow by ?20–50%. Overall, our findings indicate that L- and T-type Ca2+ channels are expressed in cerebral arterial smooth muscle and can be electrically isolated from one another. Both conductances contribute to myogenic tone, although their overall contribution is unequal. Режим доступа: по договору с организацией-держателем ресурса |
| Language: | English |
| Published: |
2013
|
| Subjects: | |
| Online Access: | http://ajpheart.physiology.org/content/304/1/H58.full-text.pdf+html |
| Format: | Electronic Book Chapter |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=639020 |