The laboratory exercise described in this article used a simple preparation and a straightforward protocol to illustrate how the neurotransmitter norepinephrine (NE) induces an increase of tension in an artery. This was a practical class designed for undergraduate students of the University of Tours. The students performed several protocols to understand how NE acts to contract aortic ring vessels, which sources of calcium are mobilized, and whether the calcium sensitivity of the contractile regulatory apparatus is involved. The design of this exercise allowed students to participate actively in an exercise demonstrating that many mechanisms are involved and act additively to allow arterial tone to develop. Furthermore, the students were introduced to an isolated organ chamber technique that is used to study cellular mechanisms of many tissues and that is still important for smooth muscle research.

Key words: vascular contraction; arterial pressure; smooth muscle cell; teaching