Extracellular acidification related to the stimulation of catecholamines release by strontium in the bovine adrenal medulla.

The possible modifications of extracellular pH associated with the secretion of catecholamines evoked by the introduction of 2.2 mM Sr2+ to a Ca(2+)-free, buffer-free, Locke solution were investigated in decorticated perfused bovine adrenal glands. A progressive and reversible decrease of external pH accompanied the catecholamine release promoted by Sr(2+)-introduction into the perfusion fluid.

Effect of hyperosmolarity on extracellular acidification associated with catecholamine secretion evoked by barium in perfused bovine adrenal medulla.

1. The effects of the increase of osmotic strength on extracellular pH modifications produced during buffer-free, 5 mM Ba2+ stimulation was studied in decorticated perfused bovine adrenal glands. 2.

Characterization of extracellular pH drop due to the activation of the secretory process by acetylcholine in the bovine adrenal medulla.

A progressive and reversible decrease of external pH accompanied the catecholamine release elicited by acetylcholine in decorticated bovine adrenal glands perfused with buffer-free Locke solution adjusted to an initial pH of 7.4. Both the secretory response as well as the extracellular acid shift promoted by the cholinergic agonist were antagonized by hexamethonium plus atropine, Mg2+ and verapamil.

In vitro evaluation of acute effects of mitoxantrone (Novantrone) in rat and guinea pig atria.

Since guinea pig and rat atria have been used as models to study acute anthracycline-induced cardiotoxicity, experiments were carried out in these preparations to evaluate possible acute cardiac effects mediated by mitoxantrone (MTX). After a latency period of approximately 90 min, MTX (10(-5)-10(-4) M) promoted a concentration-related and time-dependent decrease of spontaneous rate in guinea pig atria. A similar but less intense effect after a longer latency interval was observed in rat atria.

Decrease of extracellular pH associated with the secretion of catecholamines induced by barium in perfused bovine adrenal medulla.

1. The possible modifications of extracellular pH produced during buffer-free 5 mM Ba2+ stimulation was studied in decorticated perfused bovine adrenal glands. 2.