Search PubMed⌕ Search

Biomedical subjects

I Haulică

Publications and source records attributed to I Haulică.

At least 19 recordsLinked to original sources
PubMed2004

New bioactive angiotensins formation pathways and functional involvements.

After a brief review of the actual knowledge concerning the circulating and tissue Renin-Angiotensin System (RAS) as a unitary hormonal system, the cognitive acquisitions regarding the formation and action mechanisms of the new biologically active angiotensins will be presented. The review of the enzymatic pathways for their synthesis and inactivation, as metabolism products of angiotensin II (1-8), will be followed by the presentation of the main physio-pharmacological actions of angiotensin III (2-8), angiotensin IV (3-8) and angiotensin (1-7). The functional involvements of the cerebral angiotensin IV in what concerns its possible participation in the normal neurochemical processes of memory and in the neurodegenerative processes of Alzheimer disease will be exposed, together with the vasodilating effects of angiotensin (1-7) as counteracting factor for the constricting effects of angiotensin II. The data concerning the bioactive fragments of angiotensin II will be accompanied by those regarding its implication in the cardiovascular modeling and the induction of oxidative stress, inflammation, atherogenesis, etc. In their turn, personal researches bring new experimental evidences in favor of interactions between angiotensin (1-7) and angiotensin II within the rat thoracic aorta. Biphasic, dose-dependent effects were observed for angiotensin (1-7), induced both through nitric oxide, kinins and prostaglandin release for counteracting the vasoconstricting effects of angiotensin II and the modulation of its own vasodilator action.

Angiotensins↗
PubMed1986

Evidence for the involvement of cerebral renin-angiotensin system (RAS) in stress analgesia.

Studies concerning variations of the central renin-angiotensin system (RAS) during immobilization stress in rats have shown a significant increase in renin-like activity in the hypothalamus and fronto-parietal cortex, together with a definite decrease in the hypophysis and pineal gland. The resultant stress analgesia is blocked by the previous administration of naloxone and saralasin (angiotensin II antagonist). The intracerebral administration of renin and angiotensin II produces an increase in latencies to thermoalgesic stimuli; this is reduced, as is immobilization stress, by naloxone and saralasin. Both chemical hypophysectomy obtained by dexamethasone pretreatment as well as surgical epiphysectomy block the stress-induced analgesia. The experimental data obtained argue in favour of the participation of the cerebral RAS in stress analgesia through the indirect mechanism of release of opioid peptides.

Analgesia↗
PubMed1980

Influence of angiotensin II on dog pineal serotonin content.

Intravenous infusion of angiotensin II in different concentrations for 2 h induced an increase in the serotonin contents of pineal gland, hypothalamus and brain stem in dogs. The maximal stimulatory effect was obtained with a concentration of 50 ng angiotensin II/kg body wt./min. Results are interpreted with regard to the concept of an intrinsic isorenin-angiotensin system and its implications at the level of brain nervous tissue and accessory glands. Experimental data indicating the possible existence of positive and negative feedback relationships between the brain isorenin-angiotensin system and serotonin metabolism in the pineal gland, are presented.

Angiotensin II↗
PubMedDate not supplied

[The contribution of molecular biology to the progress of the physiological sciences].

Life science, physiology have an important improvement on cell sciences, by seeing cell through a complex integrative concept. So, the notion of homeostatic equilibrium for the whole body is applied at the cellular level. Also, molecular biology techniques can facilitate the answer for a lot of the physiological and pathological questions. This paper mention only some of the many examples which justify both the importance of molecular biology for the cognitive progress of physiological and biomedical sciences and the role of physiological notions for the complexity view of molecular sciences.

Animals↗
PubMedDate not supplied

[The role of the endothelium in normal and pathological vascular reactivity].

After a short incursion concerning the morpho-chemical characteristics of the vascular endothelium, the main normal and pathological functional implications of the endothelial vasoactive substances are reviewed. A special attention is given to the myorelaxing effects of EDRF, identified as nitrogen oxide (NO) and its production mechanism, at the vascular level, with the participation of cGMP as intracellular second messenger. The literature data are completed by a part of the personal research regarding the changes of the vascular reactivity induced by the endothelial NO. Experimental proves are brought in favor of influencing of the vasconstrictor reactions produced by phenylefrin, noradrenalin and angiotensin by the NO-cGMP system. Finally, the main patho-physiological and pharmacological implications of endothelial NO are mentioned.

Animals↗
PubMedDate not supplied

[Melatonin and ubiquinone as endogenous antioxidant factors].

We studied the effect of restraint stress upon the degree of lipidic peroxidation in the fronto-temporal cerebral cortex, diencephalon, thymus and gastric mucosa. We determined the malon-dialdehyde (MDA) by spectrocolorimetry, the percentage of animals with stress gastric ulcer and the surface of gastric ulcerations. The results demonstrated an important increase of the MDA correlated with frequency and intensity of the gastric ulcer. In the second stage of the experiment, we studied the influence of the ubiquinone and melatonin on the same parameters studied in the first part. In every structures these two substances had antioxidative effect. For ubiquinone, results showed significant variations in the thymus and gastric mucosa, while at the cerebral level the results were doubtful. As antioxidant and antiulcerogenic factor, melatonin was more effective than ubiquinone, because determined significant decrease, or even disappearance of the peroxidative process in the cerebral cortex and the thymus and significantly diminished both peroxidation and ulcerogenesis in the gastric mucosa.

Animals↗
PubMedDate not supplied

[Ginkgo biloba extract (EGb 761) as an antioxidant factor of exogenous origin].

Extracted from Ginkgo biloba leaves, the EGb 761 has a great number of therapeutical properties and anti-stress effects, for example the antioxidant one. We estimated in our experiment the influence of a chronic treatment with EGb 761 on the concentration of the main product of lipidic degradation--malondialdehyde (MDA), in cerebral cortex, in diencephalon, thymus and gastric mucosa. The experiment was performed on Wistar rats, male, young. The MDA estimation was performed by the spectrocalorimetry. We have determined that the stress raised the MDA concentration in all examined structures with approximately 100% and 80% of animals manifested stress ulcer. The treatment with EGb 761 before a stress inhibits the post-stress growth of MDA concentration and the process of stress ulcer formation.

Animals↗
PubMedDate not supplied

[Current data on the extrarenal renin-angiotensin system].

After a brief historical incursion regarding SRA of renal origin we present the main extrarenal angiotensin-forming enzymes, starting with isorenin, tonin, cathepsin D şi G and ending with the conversion enzyme and chymase. This is followed by a short presentation of data concerning tissue SRA in the heart and vessels, brain and neurocranial accessory glands, cortico-suprarenalian and gonadal glandular territory. In the end we refer to the relations between circulating SRA of renal origin and the tissue extrarenal one, underlying the fact that the two SRA components cooperate and constitute a unitary hormonal system, towards the regulation of the major functions of the organism and the maintenance of the main homeostatic equilibria. While the circulating SRA of renal origin is acutely activated to contribute to the accomplishment of short term homeostatic reactions, tissue SRA, in paracrine or autocrine ways, exerts loco-regional adaptive actions of long duration.

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

Effects of heavy and deuterium-depleted water on vascular reactivity.

The comparative study of heavy and deuterium-depleted water on the vascular reactivity has shown significant changes of the basal tone in the smooth muscle of the rat thoracic aorta rings. While the heavy water induced relaxing effects, the deuterium-depleted water increased basal tone and vasoconstrictor responses at phenylephrin, noradrenalin and angiotensin. Endothelial nitric oxide seems to be involved in generating the muscular relaxing effects of heavy water.

Angiotensins↗
PubMedDate not supplied

Preliminary research on possible relationship of NO with agmatine at the vascular level.

The comparative study of the vascular effects of agmatine and L-arginine as physiological precursors of NO indicated the following: When administered intravenously, both vasoactive substances produced a decrease of the systemic blood pressure in rats and rabbits, diminished in the case of agmatine and suppressed in that of arginine by the previous administration of L-NAME. Myorelaxing vascular effects were obtained in isolated thoracic aorta rings, precontracted with phenylephrine and noradrenaline. Endothelium removal suppressed the myorelaxing properties of L-arginine, without affecting the effects of agmatine, both before and after administration of L-NAME or yohimbine. The persistence of the relaxing effects of agmatine after NOS and guanylate-cyclase inhibition with methylene blue excludes the participation of NO and cGMP in their occurrence. The enhancement of agmatine myorelaxation by moxonidine pleads for the stimulation of imidazoline receptors.

Agmatine↗