Pro-contractile role of chloride in arterial smooth muscle: Postnatal decline potentially governed by sympathetic nerves.

NEW FINDINGS: What is the topic of this review? This symposium report discusses the previously unrecognized pro-contractile role of chloride ions in rat arteries at early stages of postnatal development. What advances does it highlight? It highlights the postnatal decline in the contribution of chloride ions to regulation of arterial contractile responses and potential trophic role of sympathetic nerves in these developmental alterations. ABSTRACT: Chloride ions are important for smooth muscle contraction in adult vasculature. Arterial smooth muscle undergoes structural and functional remodelling during early postnatal development, including changes in K+ currents, Ca2+ handling and sensitivity. However, developmental change in the contribution of Cl- to regulation of arterial contraction has not yet been explored. Here, we provide the first evidence that the role of Cl- in α1 -adrenergic arterial contraction prominently decreases during early postnatal ontogenesis. The trophic influence of sympathetic nerves is a potential mechanism for postnatal decline of the contribution of Cl- to the vascular contraction.