Overview
Calcium ions are essential to contract smooth muscle cells in blood vessels. They enter these cells through voltage-dependent calcium channels, specifically L-type calcium channels in the cell membrane. These L-type calcium channels are integral to the excitation-contraction coupling process in smooth muscle. When a stimulus is received by smooth muscle cells, their membrane depolarizes. This alteration in membrane potential instigates the opening of L-type calcium channels. As a result, calcium ions are allowed to enter the cell from the external environment. The resulting increase in intracellular calcium concentration activates calmodulin, a protein that binds calcium. Calmodulin then binds to and activates myosin-light chain kinase (MLCK), which phosphorylates the light chain. This phosphorylation allows myosin to interact with actin, initiating cross-bridge cycling and culminating in smooth muscle contraction. However, if L-type calcium channels become overactive, it can lead to an excessive influx of calcium into vascular smooth muscle cells. This leads to higher cytosolic calcium levels, which can extend vasoconstriction, thereby increasing peripheral resistance and raising blood pressure. Calcium channel blockers, such as dihydropyridines like amlodipine, nicardipine, and felodipine, block these voltage-gated calcium channels. They attach to the α1 subunit of the calcium channels, inhibiting calcium ions' entry into the cell. This action leads to a …
Embed Tool
Show this article's:
Embed code vs URL
An embed code allows you to place a JoVE video directly inside of your learning or training environment. Most learning management systems such as Canvas, Blackboard, and Moodle require an embed code for JoVE content to stream.
A URL allows you to place a link in programs such as PowerPoint or Microsoft Word which takes a user to a separate page where they can watch a JoVE video.
Most of the time, you will want to use the embed code. However, there are some environments that don’t support embed codes such as Google Classrooms and MS Teams. In those instances, you can use a URL to still provide access to JoVE videos.
What is an Embed Code?
Basically, it’s a snippet of code that you put on your website that displays as a video. An embed code pulls the video from the original source, allowing you to display a video without having to host the file on your website.
How to embed a video
STEP 1: COPY YOUR EMBED CODE
To generate the embed code, simply click the Copy button above. You can customize it by choosing a specific language for the video, or setting exact dimensions for the video player.
STEP 2: PASTE THE EMBED CODE INTO YOUR ENVIRONMENT
Embed codes can be used in most learning management systems (Canvas, Blackboard, Moodle…), organizational websites, and a host of other tools. The specifics of how to add in an embed code will depend on your environment.
Generally, it involves accessing a text editor, entering the HTML mode on the editor, and pasting in the embed code. Get more details on embedding into specific environments here.