URINARY EXCRETION OF CATECHOL AMINES IN THE RAT AFTER THEIR LIBERATION BY RESERPINE OR DEXAMPHETAMINE

Argentinean Society of Experimental Pharmacology: Brief history and main scientific contributions to the discipline

Argentina Biomedical Science has been historically strong. The development of Human and Veterinary Pharmacology in our country as a pivotal discipline has been acknowledged worldwide because of the quality of its contributions. Argentinean Society of Experimental Pharmacology (SAFE) is a non- profit association whose research fields include Experimental and Clinical Pharmacology. SAFE main goals are described as follow (a) To meet active researchers for studying concerns regarding Experimental and Clinical Pharmacology (b) To launch an initiative for development of the discipline in mainly our country and other collaborative countries worldwide (c) To spread the pharmacological know-how obtained from different research teams (d) To strengthen relations between pharmacologists (e) To facilitate the presentation and discussion of scientific papers. This current article shows the SAFE's more important scientific contribution to pharmacology through its former research scientists to the present.

High concentrations of atrial natriuretic peptide and brain natriuretic peptide in rat pericardial fluid and their reduction by reserpine in vivo

We determined concentrations and molecular sizes of natriuretic peptides in rat pericardial fluid and plasma by use of specific radioimmunoassays (RIA) and gel filtration HPLC. Our study shows that pericardial fluid forms a local extracellular storage of immunoreactive (ir) atrial natriuretic peptide (irANP) and brain natriuretic peptide (irBNP) near the heart where these peptides can be found in high concentrations in vivo. The concentrations of irANP, irBNP and NH2-terminal fragment of proANP (irNT-proANP) in pericardial fluid were 9.8 +/- 3.7, 0.49 +/- 0.47 and 28.9 +/- 11.8 nmol/l, respectively. IrBNP had the lowest (20 +/- 11) and irANP the highest (90 +/- 32) concentration ratio between pericardial fluid and plasma. The elution positions of irANP, irBNP and irNT-proANP in pericardial fluid and plasma were similar as examined by gel filtration HPLC. Furthermore, we show that the reduction of noradrenaline content of the heart muscle by reserpine reduces concentration of irANP in pericardial fluid by 39.6% and in plasma by 30.3% when compared to respective control group values. The concentration of irBNP is reduced by 44.1% in pericardial fluid but in plasma its reduction was not statistically significant. Vasoactive peptides released into the interstitial space and from there into pericardial fluid may have a more active role in the regulation of cardiac function than previously considered.

Effects of guanethidine on the blood pressure response to splanchnic nerve stimulation in the rat: role of the adrenal medulla

1. Splanchnic nerve stimulation provokes a larger increase in blood pressure in intact rats than in rats previously demedullated by means of expression of the adrenals in situ and adrenalectomy followed by adrenocortical grafting.2. Rats pretreated with guanethidine showed an attenuated albeit prolonged hypertensive response to splanchnic stimulation. Similar effects were exerted by guanethidine in rats demedullated by expression. In rats demedullated by grafting, smaller doses of guanethidine induced a more substantial depression of the blood pressure response without increasing its duration.3. It is concluded that inhibition of the peripheral sympathetic endings induced by guanethidine was partially compensated by the enhancement of the cardiovascular effects of the mediators released by the adrenal medulla and that demedullation by expression did not completely eliminate chromaffin tissue.