Impaired thermoregulation in pregnant rabbits at term

Membrane potential and resistance measurements were carried out on segments of superfused mouse exorbital lacrimal glands by inserting two microelectrodes into neighbouring coupled cells.Short-lasting intracellular injections of Ca²⁺, by the method of microiontophoresis, caused membrane hyperpolarization and resistance reduction. These effects were also observed in the presence of adrenergic and cholinergic blocking agents. From the potential and resistance changes observed the null potential for the action of Ca²⁺ was calculated to be –50 mV.Short-lasting extracellular Ca²⁺ applications caused membrane hyperpolarization and resistance reduction, but these effects were blocked by a combination of atropine and phentolamine.Intracellular Ca²⁺ application mimics the action of adrenaline and acetylcholine on lacrimal acinar cells.