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R Gaggi

Publications and source records attributed to R Gaggi.

At least 37 records · Page 2Linked to original sources
PubMed1992

Calcitonin enhances the effects of nimodipine on biogenic amines of rat brain.

1. Nimodipine affects the brain biogenic amines suggesting both inhibition of the striatal dopaminergic system and activation of serotonergic systems in various brain areas. 2. Salmon calcitonin affects serotonergic systems as nimodipine does. 3. It was hypothesized that these effects could be more than additive since they all have been ascribed to inhibition of neuronal calcium influx. 4. Biogenic amines and metabolites were determined in brain areas obtained from rats pretreated with saline or salmon calcitonin (10 MRC U/kg, s.c.) and treated with nimodipine (2.5-20 mg/kg, i.p.). 5. The effects of nimodipine and salmon calcitonin appeared to be merely additive.

Animals↗
PubMed1992

Effects of nitrendipine and nisoldipine on biogenic amines in discrete areas of rat brain.

1. Biogenic amines and metabolites were determined in discrete brain sections obtained from rats once or repeatedly treated with nitrendipine or nisoldipine. 2. The increase in both the 5-HIAA levels and the 5-HIAA/5-HT ratio suggested that the drugs activated the serotonergic system in various brain areas. 3. Moreover, nisoldipine decreased the HVA content and the HVA/DA ratio in the striatum. 4. This suggested that nisoldipine, but not nitrendipine, inhibited dopaminergic neurotransmission in this brain area. 5. The effects induced by repeated treatment with nitrendipine or nisoldipine were reduced as compared to those caused by a single administration of these drugs. 6. All these facts could be explained on the basis of the pharmacokinetic properties of nitrendipine and nisoldipine and by the ability of these drugs to interact with the brain VSCC.

Animals↗
PubMed1992

Long-term comparison between captopril and nifedipine in the progression of renal insufficiency.

To verify the hypothesis that angiotensin-converting enzyme (ACE) inhibitors possess a unique renoprotective effect in progressive chronic renal disease, we decided to compare the effects of an ACE inhibitor and a calcium antagonist on both hypertension and the progression of non-diabetic renal insufficiency in a long-term study. A four-year, multicenter, prospective, randomized trial was conducted on 142 hypertensive patients (pts) with established chronic renal failure from six Italian nephrology departments. They were on standard antihypertensive therapy with a low-protein diet and underwent twice-monthly surveillance for a one year pre-randomization period. After that year, 121 pts were randomly allocated to captopril or slow-release nifedipine therapies for a three-year study period. The progression of renal insufficiency was monitored every two months. Blood pressure control was significantly better after randomization than during the year of standard antihypertensive therapy. The progression rate before randomization (BR) was definitely higher before than after randomization (AR): Creatinine clearance (CCr) change BR = -0.46 +/- 0.45 ml/min/month, creatinine clearance change AR = -0.23 +/- 0.43 ml/min/month (P less than 0.01). After randomization, the mean blood pressure values were virtually the same throughout the three year period of the study in the two groups treated by captopril (group I), or nifedipine (group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effects of nimodipine on biogenic amines in discrete brain areas.

Discrete brain sections were obtained from rats after once or repeatedly given intraperitoneal nimodipine at doses ranging from 2.5 to 40 mg/kg. The single or the last treatment was carried out at 2-8 h before killing. The biogenic amine and metabolite content of the tissue samples were determined by high-performance liquid chromatography with electrochemical detection. The nimodipine-induced effects, chiefly regarding the brainstem, the thalamus-midbrain and the striatum, consisted of both an increase in 5-hydroxyindoleacetic acid (5-HIAA) levels and a decrease in dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels. Since the 5-HIAA/5-hydroxytryptamine (5-HT) ratio was increased, whereas the DOPAC/dopamine (DA) and HVA/DA ratios were decreased, it was argued that nimodipine activated the serotonergic and inhibited the dopaminergic systems. The first effect was enhanced by fasting and, likewise, by drug administration repeated for 5 days, while the second was not affected by fasting, but disappeared after 5 days' treatment. The data obtained appeared to substantiate the usefulness of nimodipine to treat some disorders of the central nervous system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Prognostic value of captopril renal scintigraphy in renovascular hypertension.

This study evaluates the prognostic value of captopril renal scintigraphy in hypertensive patients undergoing renal artery revascularization. Preoperative studies of 51 patients were correlated with blood pressure results at 6- and 12-mo follow-up. Captopril-renal scintigraphy was carried out 1 hr after oral administration of 50 mg of captopril, using either 220 MBq of 99mTc-DTPA or 74 MBq of 99mTc-MAG3, followed by a baseline study in case of abnormal results. Evidence of amelioration or normalization in relation to captopril study was considered predictive of blood pressure control following treatment. Blood pressure response was favorable in 37 patients, but failed to show any improvement in 14. The scintigraphic test was positive in 33 patients (15 cured, 17 improved, 1 failed) and negative in 18 (3 cured, 2 improved, 13 failed). Sensitivity and specificity for renovascular hypertension was 86.5% and 93%, respectively. For blood pressure cure and improvement, the test had positive and negative predictive values of 97% and 72%, respectively. A positive preoperative captopril renal scintigraphic result is a strong predictor of hypertension curability by renal artery revascularization.

Adult↗
PubMed1991

Effects of brain biogenic amines of repeated treatments with calcium antagonists.

Discrete brain sections were obtained from rats once or repeatedly (once a day for 5 days) given i.p. nifedipine, verapamil or diltiazem at doses ranging from 5 to 20 mg/kg. The biogenic amines and metabolites in the hypothalamus, brainstem, hippocampus, striatum, cortex and thalamus-midbrain were determined by high-performance liquid chromatography with electrochemical detection. The drug-induced changes, displaying regional specificity and differences according to the various compounds, suggested that: (a) serotonergic systems were activated, especially in fasted rats or after repeated treatment; (b) the dopaminergic system of the striatum was inhibited by nifedipine which did reduce the HVA levels and the HVA/DA, as well as the DOPAC/DA, ratio. These effects disappeared after repeated treatment. It was also speculated that the data obtained could be of great interest in view of the possible use of calcium antagonists to treat disorders of the central nervous system.

Animals↗
PubMed1990

Effects of calcium antagonists on biogenic amines in discrete brain areas.

Discrete brain sections were obtained from rats given i.p. verapamil, nifedipine, diltiazem or flunarizine (0, 10, 20 or 40 mg/kg). The biogenic amines and metabolites in the hypothalamus, brainstem hippocampus, striatum, thalamus-midbrain and cortex were determined by high-performance liquid chromatography with electrochemical detection. The treatments induced several changes in the levels of neurotransmitters and metabolites, displaying regional specificity and differences according to the various compounds. It was speculated that some effects could have been due to indirect actions and/or to interactions of the compounds with receptors other than the voltage-sensitive calcium channels. However blockade of these channels could account for the following effects. (a) The nifedipine-induced increases in the 5-hydroxy-3-indoleacetic acid levels and, in general, the signs of activation of the serotonergic systems. (b) The fall in the 3,4-dihydroxyphenylacetic acid levels and, in general, the signs of attenuation of dopaminergic neurotransmission induced by nifedipine, verapamil and diltiazem. (c) The fall in the norepinephrine levels induced by all the compounds studied.

Animals↗
PubMed1989

Relationships between the effects of peripherally administered salmon calcitonin on calcaemia and brain biogenic amines.

The effects of s.c. administered salmon calcitonin on the biogenic amine neurotransmitters and metabolites were studied in discrete brain sections in order to evaluate the relationships between these central effects and the fall of serum calcium and to investigate the mechanisms of calcitonin-induced behavioral changes. The biogenic amines and metabolites were simultaneously determined by high-performance liquid chromatography with electrochemical detection in tissue samples obtained from rats treated with 10-80 MRC U/kg of the peptide. Some rats were pretreated with calcium lactate to inhibit the calcitonin-induced hypocalcaemia. Most of the effects, consisting of signs of serotonergic system activation, have been observed in the hypothalamus, accounting for some behavioral effects of the peripherally administered salmon calcitonin. It was speculated that the activation of the brain serotonergic system could result from two indirect and separate mechanisms: the first, which would involve enhanced serotonin synthesis, seemed to be facilitated by calcium availability. A second possible mechanism, which would involve enhanced serotonin release from the neurons, seemed to be mediated by the fall of calcium levels in the blood.

Animals↗
PubMed1989

Renal functional reserve in patients with a reduced number of functioning glomeruli.

Renal functional reserve (RFR) has been reported to be either reduced or absent in patients with renal insufficiency. Our study consisted in measuring RFR by acute protein load (PL) in 3 groups of patients: the first one was composed of 20 patients (pts) with biopsy-proven glomerular disease (GN) and a varying percentage of sclerotic glomeruli (15-70%); the second one consisted of 10 patients with acquired single kidney (SK) and the third group contained 5 patients with surgical ablation of more than 50% renal tissue (LRRM). Twenty-four healthy volunteers were studied as control subjects. The GFR percentage increase (delta GFR%) after PL in CS did not differ from that of the three groups of patients, despite a significant difference in resting GFR (CS = 113 +/- 11 ml/min/1.73 m2: GN 72 +/- 28 ml/min/1.7, p less than 0.01 vs CS; SK 81 +/- 20 ml/min/1.73 m2, p less than 0.01 vs CS; LRRM 45 +/- 10 ml/min/1.7, p less than 0.01 vs CS; Moreover, an inverse correlation was not found either between GFR and the percentage of sclerotic glomeruli in GN (r = 0.01, p = NS) or between GFR and the extent of excised renal tissue in the other two groups (r = 0.38, p = NS). In conclusion, our data do not confirm that RFR is necessarily reduced or absent in patients with a reduced number of functioning glomeruli, nor do they uphold the hypothesis of constant hyperfiltration in the remaining glomeruli.

Adolescent↗
PubMed1989

Evaluation of hypertensive patients by means of captopril enhanced renal scintigraphy with technetium-99m DTPA.

One-hundred five hypertensive patients underwent conventional renal scintigraphy followed 2 or 3 days later by Captopril-enhanced renal scintigraphy, performed 1 hr after premedication with 50 mg of Captopril per os. All patients were then submitted to renal arteriography, performed within 15-30 days. Fifty-five patients had no renal artery stenosis, 29 had unilateral disease, and 21 bilateral. Overall, 34/37 patients were diagnosed by the provocative test as having at least one renal artery affected by a stenosis greater than 50%. Of those with no stenosis (n = 55) or stenosis less than 50% (n = 13) only two cases were falsely positive. Thus sensitivity was 92% and specificity 97%. For single kidney identification with stenosis greater than 50%, sensitivity of renal scintigraphy after Captopril administration was 94% and specificity 98%. Captopril enhanced renal scintigraphy is thus suggested as the first test to be performed in hypertensive patients referred for renal scintigraphic studies. Only those cases with equivocal results require a baseline study for better assessment.

Adult↗
PubMed1988

Salmon calcitonin induced head twitch in the rat.

The intracerebroventricular administration of salmon calcitonin (sCT) to rats induced a dose-dependent increase in the number of head twitches and potentiated such a response elicited by L-5-hydroxytryptophan (L-5-HTP). Subcutaneously administered sCT was ineffective "per se" but could again potentiate the head twitch response elicited by L-5-HTP. Since these data suggest a stimulation of the brain serotonergic pathways, the obtained results support the hypothesis that some central actions of sCT may involve activation of serotonergic systems in the rat brain.

5-Hydroxytryptophan↗