Contraction of smooth muscle by activation of endothelin receptors on autonomic neurons.

Endothelin receptors, predominantly of the ETB type, were localized to cell bodies, processes, and varicosities of cholinergic and adrenergic intramural autonomic neurons that were present in primary cultures of guinea pig tracheal smooth muscle. Stimulation of the neuronal ETB receptor produced a tetrodotoxin-sensitive increase in the intracellular calcium concentration in neurons which was followed by contraction of the neighboring smooth muscle cells. These observations suggest that endothelins can induce smooth muscle contraction by means of a neuronally mediated mechanism, in addition to their direct actions on the smooth muscle.