English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

—We have found nifedipine-insensitive (NI), rapidly inactivating, voltage-dependent Ca2+ channels (current, NI-I Ca ) with unique biophysical and pharmacological properties in the terminal branches of guinea pig mesenteric artery, by using a whole-cell mode of the patch-clamp technique. The fraction of NI-I Ca appeared to increase dramatically along the lower branches of mesenteric artery, amounting to almost 100% of globalI Ca in its periphery. With 5 mmol/L Ba2+ as the charge carrier, NI-I Ca was activated with a threshold of −50 mV, peaked at −10 mV, and was half-activated and inactivated at −11 and −52 mV, respectively, generating a potential range of constant activation near the resting membrane potential. The NI-I Ca was rundown resistant, was not subject to Ca2+ -dependent inactivation, and exhibited the pore properties typical for high voltage–activated Ca2+ channels; Ba2+ is ≈2-fold more permeable than Ca2+ , and Cd2+ is a better blocker than Ni2+ (IC50 , 6 and 68 μmol/L, respectively). Relatively specific blockers for N- and P/Q-type Ca2+ channels such as ω-conotoxins GVIA and MVIIC (each 1 μmol/L) and ω-agatoxin IVA (1 μmol/L) were ineffective at inhibiting NI-I Ca , whereas nimodipine partially (10 μmol/L; ≈40%) and amiloride potently (≈75% with 1 mmol/L; IC50 ; 107 μmol/L) blocked the current. Although these properties are reminiscent of R-type Ca2+ channels, expression of the α1E mRNA was not detected using reverse transcriptase–polymerase chain reaction. These results strongly suggest the predominant presence of NI, high voltage–activated Ca2+ channels with novel properties, which may be abundantly expressed in peripheral small arterioles and contribute to their tone regulation.

Predominant Distribution of Nifedipine-Insensitive, High Voltage–Activated Ca 2+ Channels in the Terminal Mesenteric Artery of Guinea Pig

Predominant Distribution of Nifedipine-Insensitive, High Voltage–Activated Ca ²⁺ Channels in the Terminal Mesenteric Artery of Guinea Pig