Biomedical subjects

S M Slătineanu

Publications and source records attributed to S M Slătineanu.

5 recordsLinked to original sources

PubMedDate not supplied

[The physio-pharmacological and pathological implications of the endothelins].

The papers of Furchgott and Zawadzki have widely enlarged the research field concerning the dependence of the vascular smooth muscle reactivity upon the endothelium. Besides the relaxing factors produced by the endothelium, vasoconstrictor factors have been also emphasized. The endothelial cells are also able to synthesize endothelin-like vasoconstrictor peptides. There were described some types of endothelins. They all have common structural features but substitution of certain amino-acids leads to specific effects, and all of them keep the vasoconstrictor properties. The endothelins are normal constituents of a lot of tissues (brain, endothelial and tumor cells, the spinal nodes) and of the body fluids (plasma, urine, cerebrospinal fluid etc.). The endothelins accomplish their effects by the specific receptors located in the muscle and endothelial cell membrane (ET-A and, respectively, ET-B). The endothelins action in the cell is basically based on the cytosolic Ca2+ raise. The endothelins have numerous pathological implications, especially concerning the cardiovascular pathology.

Animals↗

PubMedDate not supplied

[Dipsogenic behavior].

Hydroelectrolytic homeostasis assumes balance between the intake and elimination of water and electrolyte, according to the necessities of the organism. The water intake is made mainly by fluid ingestion. The necessity to drink is a subjective sensation which is the expression of an objective situation, because it translates the homeostatic deviations. The ingestion of water is motivated (reparatory thirst), when it appears after hydric and electrolytic imbalances (ex. a decrease of the fluid volume, increase in the plasmatic osmolarity) or is manifested without an objective reason (unreparatory thirst).

Animals↗

PubMedDate not supplied

[The effects of the intraventricular administration of captopril on water and ion metabolism in the rst].

The effects of the conversion enzyme on the hydroelectrolytic balance in adult rats, maintained in standard lab conditions have been followed. The administration protocol for the conversion inhibitor (captopril) produced a blocking of the transformation of angiotensin I in angiotensin II only at the level of the cerebral structures, during the whole period of the treatment (40 micrograms/kg x 3/24 hours). Following the intracerebroventricular (ICV) administration of captopril, the fluid ingestion decreased diuresis and urinary elimination of Na+ and Ca++ increased. The results plead for the existence of a cerebral renin-angiotensin system, which intervenes in the control of the hydroelectrolyte metabolism.

Angiotensin-Converting Enzyme Inhibitors↗

PubMedDate not supplied

Implications of imidazolines and imidazoline receptors role at the vascular level.

There are both post- and pre-synaptic vascular imidazoline (IM) binding sites. The importance of direct IM actions and that of peripheral imidazoline receptors (IRs) are shadowed by the central effects of IMs and by their interaction with alpha 2 adrenoceptors. Since the discovery of clonidine the many studies on IMs have been focused on their hypotensive effect, with rilmenidine and moxonidine as representative drugs. Formerly called IM preferring alpha 2 or IM/guanidium sites, the IRs (idazoxan-sensitive) are the plasmalemmal I1 (clonidine-sensitive) and the various I2 (one structure identified as MAO). I1 signaling includes activation of phosphatidylcholine-selective phospholipase C and inhibition of some ligand-gated channels. Inhibitory IRs on postganglionic sympathetic terminals, are not alpha 2, H3, I1 or I2. Some IMs directly affect CaL, while others inhibit K+ efflux. Clonidine-displacing substances including agmatine are endogenous ligands at IRs and alpha 2 and may participate in arterial pressure control. Beside few speculations, the roles of vascular IRs are largely unknown.

Antihypertensive Agents↗

PubMedDate not supplied

Contractile effects of intracellularly administered angiotensin II are partially dependent on membrane receptors internalization in isolated rat aorta.

In the present study we used the isolated rat aorta as a model to characterize the modulation of contractile effects of extra- and intracellularly administered angiotensin II by dithiothreitol (DTT) and hyperosmotic sucrose. DTT inactivation of AT1 receptor as well as disruption of the clathrin-coated pits by hyperosmotic sucrose significantly inhibited the contraction induced by intracellularly administered AII. We suggest that these intracellular effects of angiotensin peptides are associated with AT1 receptor activation/internalization and may thus be part of the mechanism of angiotensin peptides direct contractile effects in the vascular smooth muscle.

Angiotensin II↗