[Use of calciotropic agents in psychiatry and neurology]

Neurotransmission of impulses is a phenomenon activated by the calcium signal. Therefore changes of calcium homeostasis in the nerve cell always influence more or less this function. Changes of calcium homeostasis in the nerve cell occur under various pathological conditions, incl. hypoxia. The cytosol of the neuron is excessively saturated with calcium ions due to a shift from the extracellular space. The affected neurons release humoral factors, so-called neurotransmitters, which by receptor-controlled activation of calcium channels enhance the calcium influx from the extracellular space. After exhaustion of defense mechanisms by which the nerve cell gets rid of excessive calcium its metabolism is affected and necrosis may occur. This toxic effect of calcium can be prevented by administration of calcium antagonists represented by 1. blockers of slow calcium currents and 2. calmodulin inhibitors. The author gives an account of antipsychotic, analgetic, myorelaxing and vasodilatating effects of some calcium antagonists, and their clinical application is discussed. The author emphasizes also some possible undesirable effects of some neuroleptics mediated by the calciotropic mechanism, in particular during long-term administration. They are manifested by increased urinary calcium losses and impaired bone mineralization. Delayed regression of myorelaxation during anaesthesia is also important and must be taken into account in patients treated for prolonged periods with blockers of calcium currents.