Related Experiment Video
Updated: Aug 29, 2026

Utilizing the Precision-Cut Lung Slice to Study the Contractile Regulation of Airway and Intrapulmonary Arterial Smooth Muscle
Published on: May 5, 2022
5-HT induces an arachidonic acid-sensitive calcium influx in rat small intrapulmonary artery
Christelle Guibert1, Roger Marthan, Jean-Pierre Savineau
1Laboratoire de Physiologie Cellulaire Respiratoire, Institut National de la Santé et se la Recherche Médicale, Université Bordeaux 2, 146, rue Léo Saignat, 33076 Bordeaux Cedex, France. christelle.guibert@u-bordeaux2.fr
Abstract:
5-Hydroxytryptamine (5-HT) is a potent pulmonary vasoconstrictor and contributes to hypoxic pulmonary vasoconstriction and pulmonary arterial hypertension. Small intrapulmonary vessels are very sensitive to hypoxia and play a major role for blood flow regulation in the lung. Thus we have investigated the mechanisms involved in the calcium signal to 5-HT in rat small intrapulmonary artery (IPA). Effects of 5-HT were examined in isolated IPA (external diameter <250 microm) from rat. Digital imaging with fura-PE3 was used to record intracellular calcium concentration ([Ca(2+)](i)) and to follow external diameter of the vessels. 5-HT induced a sustained [Ca(2+)](i) variation that was sensitive to the inhibitor of the 5-HT(2A) receptors, ketanserin, and insensitive to voltage-dependent L-type calcium channel blockers (nitrendipine and nicardipine) or voltage-independent calcium channel antagonists (LOE-908, SKF-96365, and gadolinium). The calcium response to 5-HT was also not modified by a sarcoplasmic reticulum Ca(2+)-ATPase inhibitor (cyclopiazonic acid; CPA), which depletes intracellular calcium stores. CPA alone activated a capacitative calcium channel that was sensitive to LOE-908 and insensitive to SKF-96365 and gadolinium. The sustained calcium signal to 5-HT was partly blocked by inhibitors of arachidonic acid production (RHC-80267 and isotetrandrine) and mimicked by application of exogenous arachidonic acid. These results suggest that activation of a noncapacitative, arachidonic acid-sensitive, receptor-operated calcium channel contributes to 5-HT-induced sustained calcium increase in small IPA.
Related Concept Videos
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Nitric Oxide Signaling Pathway
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
G-Protein Gated Ion Channels
Sensory organs,...
IP3/DAG Signaling Pathway

