K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration.

Calcium-activated potassium (K(Ca)) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of K(Ca) channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of K(Ca) channels were anticipated on the basis of their physiological and pharmacological profiles, and cloning revealed two well defined but phylogenetic distantly related groups of channels.

Measurement of [Ca²+]i in cell suspensions using indo-1.

Intracellular calcium, in particular the cytosolic free ionized calcium concentration [Ca(2+)](i), is tightly regulated under physiological conditions. Stimulation of receptors, belonging to almost all the classes so far described, will result in changes in [Ca(2+)](i). These changes might be directly induced by either Ca(2+)-influx or Ca(2+)-mobilization from intracellular stores, or indirectly by a number of other mechanisms.

Acetylcholine: a novel regulator of airway smooth muscle remodelling?

Increased airway smooth muscle mass is a pathological feature that asthma and chronic obstructive pulmonary disease (COPD) have in common. This increase has gained renewed interest in view of recent developments showing that airway smooth muscle, instead of solely being a contractile partner, is capable of interacting dynamically with its environment, especially under inflammatory conditions. Airway smooth muscle cells are able to proliferate, to migrate, and to secrete chemokines, cytokines, extracellular matrix proteins and growth factors, and most importantly, to adapt to these functions by changing its phenotype from contractile to proliferative/synthetic.

Intracellular Angiotensin II and cell growth of vascular smooth muscle cells.

1. We recently demonstrated that intracellular application of Angiotensin II (Angiotensin II(intr)) induces rat aorta contraction independent of plasma membrane Angiotensin II receptors. In this study we investigated the effects of Angiotensin II(intr) on cell growth in A7r5 smooth muscle cells.