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Biomedical subjects

G Costa

Publications and source records attributed to G Costa.

At least 253 records · Page 14Linked to original sources
PubMed1986

Cerebral cholinergic control of rat arterial blood pressure in streptozotocin-induced diabetes.

Rats were made diabetic with a single intravenous injection of streptozotocin (STZ; 40 mg/Kg). Buffer treated animals were used as controls. Experiments were performed 7 and 14 days thereafter. One week diabetic rats (plasma glucose = 3.34 +/- 0.58 mg/ml), compared with control animals (plasma glucose = 0.94 +/- 0.33 mg/ml), showed higher (P less than 0.05), more prolonged and dose-dependent pressor and bradycardic responses to intracerebroventricular (icv) injection of carbachol (125, 250 and 500 ng), together with a significantly lower bradycardia after icv injection of physostigmine (1.25, 2.5 and 5 mcg). The pressor response to icv injection of physostigmine (1.25 mcg) was significantly reduced in diabetic rats. Pressor and bradycardic responses induced by angiotensin II (100 and 200 ng, icv) did not show any differences between control and diabetic animals, thus ruling out an impairment of peripheral nerve conduction. Diabetic rats exhibited higher content of acetylcholine (Ach) in the striatum (123.8 +/- 3.09 nmoles/g) and in the hypothalamus (45.7 +/- 1.31 nmoles/g). Three weeks diabetic animals (plasma glucose = 2.76 +/- 0.23 mg/ml) had neither different cardiovascular responsiveness to icv injection of muscarinic agonists nor changes in hypothalamus and striatum Ach content. Data strongly suggest that STZ-induced diabetes temporarily alters cerebral acetylcholine control of cardiovascular apparatus.

Angiotensin II↗
PubMed1986

Alpha- and beta-adrenoceptors in the female dog urethra.

The existence and subtypes of alpha- and beta-adrenoceptors in the female dog urethra were studied in vivo and in vitro by means of agonist and antagonist drugs. Noradrenaline, phenylephrine and B-HT 920, stimulants of alpha, alpha-1 and alpha-2 receptors respectively, caused an increase in the urethra tonicity. Thus indicating that the contractile activity is mediated by alpha-1 and alpha-2 adrenoceptors subtypes. On the other hand, the inhibitory urethral activity is under control of beta-adrenoceptors of beta-2 subtype, since the isoprenaline relaxing action is inhibited when beta-2 receptors are blocked, whilst this effect was not observed when beta-1 receptors were blocked. This fact was proved when beta-2 receptors were stimulated with salbutamol.

Adrenergic alpha-Agonists↗
PubMed1986

Influence of several aldehyde dehydrogenase and aldehyde reductase inhibitors on diamine oxidase in rat brain.

Pyrroline formation in rat brain was studied in presence of different inhibitors of AldDH, AldR, ADH and MAO. The inhibition of AldDH and AldR, but not of ADH and MAO significantly increased DAO activity. The results indicate that the use of appropriate aldehyde metabolizing enzymes inhibitors allows to better understand the role of diamine oxidase in rat brain putrescine catabolism.

Alcohol Dehydrogenase↗
PubMed1985

Carbon tetrachloride-induced pharmacokinetic changes of diazepam in rats are reduced by a stable analogue of prostaglandin E2 : FCE 20700.

Rats, given CC14 (6670 mg/Kg, sc), exhibited a significant increase in SGPT (425.7 +/- 51.3 mU/ml), together with impaired pharmacokinetics of intravenous diazepam (t beta 1/2: 53.87 h; AUC: 101.05 micrograms/ml/h) when compared with saline treated animal (SGPT: 33.6 +/- 3.8 mU/ml; t beta 1/2: 2.087 h; AUC: 1.37 micrograms/ml/h). FCE 20700 (5 micrograms/ml, sc) did not change, by itself, either SGPT or diazepam pharmacokinetic parameters, but significantly antagonized the changes induced by CC14 (SGPT: 45.3 +/- 5.3 mU/ml; t beta 1/2: 0.167 h; AUC: 2.426 micrograms/ml/h). Further support to this cytoprotective effects was given by histological examination of the livers. Data indicate that this new prostaglandin E2 derivative might be useful in patients with liver failure.

Alanine Transaminase↗
PubMed1985

Effects of verapamil on the smooth muscle of the horse urinary tract.

The effects of verapamil, a calcium antagonist agent, were studied on smooth muscle preparations of the lower urinary tract of horses. Verapamil (2 X 10(-4) to 2 X 10(-8) M) relaxed the ureter, urethra and urinary bladder preparations contracted by potassium (127 mM), L-noradrenaline (2 X 10(-5) M), histamine (2 X 10(-5) M) and acetylcholine (2 X 10(-5) M). These results allow the conclusion that verapamil has a dose-dependent relaxing effect on smooth muscle of the lower urinary tract.

Acetylcholine↗
PubMed1984

Cefoperazone versus cefotaxime, plus amikacin or sisomicin, in fever and infection in hematologic granulocytopenic patients.

Forty patients with leukemia or aplastic anemia were randomized to receive one of the following antibiotic regimens at the onset of fever during granulocytopenia: cefoperazone + amikacin (regimen A), cefoperazone + sisomicin (regimen B), cefotaxime + amikacin (regimen C), cefotaxime + sisomicin (regimen D). All patients were receiving gut decontamination at the time of randomization. Patients were monitored twice weekly with swabs and cultures for bacteria and fungi. Overall, there were 56 febrile episodes: 31 were proven bacterial, 3 were probable, and 16 were of unknown origin. Response rates were comparable in all 4 treatment regimens: 90%, 91%, 92% and 92%, respectively. Three patients died of bacterial infections (2 Gram+, 1 Gram-), one patient died with probable infection, 6 febrile episodes were related to fungal infection (Candida), and 2 patients died. The mortality rate was comparable in all groups. Two patients died of renal failure. Abnormalities in liver function tests were observed, but were without consequences. There were no statistical differences in renal-hepatic toxicity in the 4 arms.

Adolescent↗
PubMed1984

Cadmium alters arterial baroreflex control of heart rate in the conscious rat.

In conscious rats, a single oral dose of cadmium (Cd) chloride (up to 150 mg/kg) does not alter mean arterial pressure, heart rate and pressor response to phenylephrine 3, 7, and 14 days after loading. However, 150 mg/kg of Cd reduce reflex bradycardia and increase centrally mediated vagal decrease in heart rate. Therefore, it is suggested that Cd could modify baroreflex control of heart rate through an impairment of the afferent component of the reflex.

Animals↗
PubMed1984

BT-Paba test in the diagnosis of pancreatic exocrine insufficiency in cystic fibrosis: urinary and serum determinations compared.

Urinary recovery and serum determination of Paba were carried out in 48 control children (C) and 53 paediatric patients with cystic fibrosis (CF) divided into three classes by age. Ninety and 120 min after the ingestion of 15 mg/kg of BT-Paba and of a standard meal, serum Paba was determined. In the same subjects the percentage Paba recovery was measured in the urine collected during an 8 h period after the same administration of BT-Paba. Correlation between urinary and serum Paba values was higher in the older children in respect to the 0-2-year-old infants. A urinary Paba test was less sensitive and specific than a serum Paba test in the evaluation of exocrine pancreatic function. The best discrimination between C and children with CF, using the maximal value of serum Paba at 90 or 120 min (peak), was obtained in the younger infants (0-2 years old). BT-Paba test with serum Paba peak determination is recommended as a substitute for the classical urinary Paba test in the evaluation of exocrine pancreatic function in paediatric patients, especially in the younger infants.

4-Aminobenzoic Acid↗
PubMed1984

The calcium antagonist nimodipine increases beta-endorphin release from rat hypophysis through an action on adrenal glands. An "in vivo" and "in vitro" study.

Intravenous injection of nimodipine (1, 10 and 100 micrograms/Kg) raised plasma ACTH and beta-endorphin (beta-EP) level and reduced pituitary beta-EP content, in the rat. These effects were sharp and short-lasting. Nimodipine (10(-8), 10(-7), 10(-6) M) did not change basal and hypothalamic extract stimulated beta-EP release from pituitary tissue in vitro. Basal release of corticosterone from adrenal glands, superfused in vitro with the calcium antagonist (10(-7) - 10(-6) M), was not modified. However, ACTH-induced release was strongly reduced. Since glucocorticoids feedback regulates biosynthesis and cleavage of pro-opiocortin, nimodipine, which reduces adrenal gland responsiveness to ACTH, might reflexly increase beta-EP release from hypophysis.

Adrenal Glands↗
PubMed1984

Shigella sonnei endotoxin reduces arterial blood pressure but does not alter pituitary pro-opiocortin cleavage and corticosterone release in the rat.

Intravenous (iv) bolus injection of 320 and 640 micrograms/Kg of lipopolysaccharides (LPS) of S. sonnei (either in phase I or in phase II) resulted in a dose-dependent decrease in mean arterial pressure, when given in freely moving rats. No changes were observed in plasma beta-endorphin (beta-EP), ACTH and corticosterone levels. Pituitary beta-EP content was not modified 1 h after iv injection of LPS. Data suggest that doses of LPS, which are able to produce reversible hypotension, do not alter pro-opiocortin cleavage and corticosterone release.

Adrenocorticotropic Hormone↗
PubMed1984

Increased cardiovascular responsiveness to GABAergic stimulation in DOCA-salt hypertensive rats.

Cerebral glutamate decarboxylase (GAD) activity in DOCA-salt hypertensive rats showed a significant increase in the mesencephalon and a significant decrease in the cerebral cortex and in the cerebellum, compared to that observed in mononephrectomized normotensive animals. Intracerebroventricular (icv) injection of muscimol (0.5, 1 and 2 micrograms), a GABA receptor agonist, produced a dose-dependent decrease in heart rate (HR), significantly greater in freely moving hypertensive animals than in normotensive controls. Muscimol also reduced mean arterial pressure (MAP). The hypotensive effect induced by muscimol (2 micrograms) was significantly higher in hypertensive animals. Ethanolamine-O-sulphate (5, 10, 20 and 40 microM), an inhibitor of GABA breakdown, determined a decrease in MAP and in HR greater in hypertensive than in normotensive rats. Intraperitoneal injection of valproic acid (50-100 mg/Kg/die) for 6 weeks significantly reduced the development of DOCA-salt hypertension in rats. The anti-hypertensive effect became significant during the 4th week and was dose-dependent. DOCA-salt animals, daily treated with 50 mg/Kg of valproic acid, showed an increased pressor response to intravenous injection of phenylephrine (0.1, 0.5 and 1 microgram/Kg). Data strongly support an impairment of cerebral GABA control of blood pressure and heart rate in DOCA-salt hypertensive rats.

4-Aminobutyrate Transaminase↗
PubMed1983

Central and peripheral sites of action for the protective effect of opioids of the rat stomach.

Rats exposed to combined cold and restraint exhibited a reduced intensity of gastric damage when pre-treated intraperitoneally with morphine HCl or with the synthetic enkephalin analog [D-Ala2, MePhe4, Met(0)5ol]enkephalin (FK 33-824). Morphine HCl and FK 33-824 prevented some of the indices of the lesion also when injected intracerebroventricularly; morphine methyliodide, quaternary derivative of morphine with does not cross the blood brain barrier, was fully effective, by intraperitoneal route, in preventing the gastric damage. Both peripheral and central mechanisms seem, therefore, involved in the protective effect of opioids on rat gastric mucosa. Morphine HCl and FK 33-824 reduced significantly gastric acid secretion when administered intracerebroventricularly or intraperitoneally; in addition, a concomitant increase of prostaglandin production was observed in rat gastric mucosa after i.p. administration of both opioids. Both these events might contribute to the protective action of opioids on the stomach.

Animals↗