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Biomedical subjects

L Berrino

Publications and source records attributed to L Berrino.

At least 73 records · Page 4Linked to original sources
PubMed1992

Antiflammins suppress the A23187- and arachidonic acid-dependent chloride secretion in rabbit distal colonic mucosa.

Antiflammins are synthetic peptides with sequence homology to proteins inhibitory for phospholipase A2. The effects of antiflammins on chloride secretion induced by the calcium ionophore A23187, arachidonic acid (AA) and prostaglandin E2 (PGE2) were investigated in distal rabbit colonic mucosa mounted in Ussing-type chambers. 100 nM AF-2 (antiflammin 2, peptide HDMNKVLDL) fully prevented the increase in Isc, net chloride secretion, tissue PGE2 and second messenger cAMP induced by 5 microM A23187. AF-1 (antiflammin 1, peptide MQMKKVLDS) also inhibited, although to a lesser extent, the A23187-mediated increase in Isc. AF-2 inhibition began at doses of 100 nM (delta Isc -0.20 +/- 0.08, microEq h-1 cm-2, mean +/- S.E.M., N = 3) and was maximal at doses comprised between 200 and 250 nM (delta Isc -0.51 +/- 0.12, microEq h-1 cm-2, mean +/- S.E.M., N = 3). AF-2 also inhibited the increase in Isc and chloride secretion induced by the incubation with 10 microM AA and bradykinin but it was ineffective when tissues were stimulated with 10 microM PGE2. 100 nM AF-2 brought about an inhibition of the increase in AA-mediated increases in PGs and cAMP comparable to that of 10 microM of the cyclooxygenase inhibitor indomethacin. In vitro assay of colonic cyclooxygenase activity showed that 100 nM AF-2 and AF-1 inhibited cyclooxygenase activity (73 and approximately 30%, respectively), but they did not modify the in vitro activity of porcine phospholipase A2.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Effects of tetanus toxin, Salmonella typhimurium porin, and bacterial lipopolysaccharide on platelet aggregation.

Endotoxins may interfere with platelet aggregation by interacting with the platelet membrane. The aim of this study was to evaluate the effects of tetanus toxin, Salmonella typhimurium porin, and bacterial lipopolysaccharide (LPS) on platelet aggregation induced by ADP and thrombin in vitro. Spontaneous platelet aggregation and platelet aggregation induced by ADP and thrombin were measured. Our results show that Salmonella typhimurium porin and bacterial LPS enhanced human and rabbit platelet aggregation induced by ADP and thrombin. Tetanus toxin did not affect platelet aggregation.

Animals↗
PubMed1992

Effects of gadolinium on N-methyl-D-aspartate (NMDA)-induced centrogenic arrhythmias.

In urethane-anesthetized rats, the intracerebroventricular (i.c.v.) administration of N-methyl-D-aspartate (NMDA)-induced central arrhythmias. These cardiac rhythm disorders could be prevented by the i.c.v. microinjection of gadolinium, an inhibitor of exocytosis. These findings suggest that inhibition of central neurotransmitter exocytosis could protect against centrogenic arrhythmias.

Anesthesia↗
PubMed1992

Research on heterocyclic compounds. XXX. Synthesis and pharmacological activity of 2-methylimidazo[1,2-b]pyridazine-3-carboxylic acids.

A group of ethyl 2-methylimidazo[1,2-b]pyridazine-3-carboxylates were prepared by reaction in anhydrous ethanol of some substituted 3-amino-pyridazines with ethyl 2-chloroacetoacetate. The corresponding carboxylic acids were obtained via alkaline or acid hydrolysis and then tested both in vivo to evaluate their antiinflammatory, analgesic and ulcerogenic actions and in vitro for their ability to inhibit the prostaglandin biosynthesis. The pharmacological results are discussed in terms of both structure-activity relationships and mechanism of action.

Animals↗
PubMed1992

Central arrhythmogenic effects of N-methyl-D-aspartate (NMDA) in anesthetized rats: influence of the denervation of the carotid-sinus baroreceptors on the susceptibility to arrhythmias.

The intracerebroventricular (i.c.v.) administration of NMDA into urethane anesthetized rats could induce centrogenic cardiac arrhythmias. There were some important differences between sodium glutamate- and NMDA-induced arrhythmias which rendered it difficult to accept the assumption that glutamate-induced arrhythmias were due to the stimulation of only NMDA receptors. Denervation of the carotid-sinus baroreceptor zones enhanced the central arrhythmogenic activity of both sodium glutamate and NMDA.

Anesthesia↗
PubMed1991

Research on heterocyclic compounds. XXVIII. Imidazo[1,2-c]pyrimidines.

A group of 24 imidazo[1,2-c]pyrimidines was taken into consideration in order to study their relationships between chemical structure and antiinflammatory activity. Some of these compounds were synthesized by us in the past, the others have been synthesized and characterized to complete the series. Antiinflammatory, analgesic, antipyretic and gastric ulcerogenic activities of such compounds were compared with those of indomethacin and discussed in terms of the effects exerted by the presence on the heterocyclic system of various substituents and an acidic or nonacidic moiety.

Acetates↗
PubMed1990

Research on heterocyclic compounds. XXVII. Synthesis and antiinflammatory activity of 2-phenylimidazo[1,2-b]pyridazine-3-carboxylic acids.

A group of ethyl esters of 2-phenylimidazo[1,2-b]pyridazine-3-carboxylic acids 3 were obtained by reaction in anhydrous ethanol of some substituted 3-aminopyridazines 1 with ethyl 2-benzoyl-2-bromoacetate 2. The acids 4 obtained via alkaline hydrolysis were tested in vivo for their antiinflammatory, analgesic and ulcerogenic actions and in vitro for their ability to inhibit the prostaglandin biosynthesis. Almost all of the new compounds showed high analgesic activity, whereas the activities exhibited in the other tests were sharply lower. These results are discussed in terms of mechanism of action.

Animals↗
PubMed1989

Interference of prenatal and postnatal exposure to Ca2+-antagonist agents on rat functional development of vascular system.

Exposure to drugs during pregnancy can alter functional development of the vascular system. The present investigation was carried out in order to evaluate the effects of prenatal and postnatal exposure to Ca2+-antagonist (diltiazem, verapamil, and nimodipine) drugs on the development of rat vasomotor reactivity. Studies were carried out on pregnant female albino rats exposed from the first day of pregnancy until weaning to diltiazem and verapamil (6 and 24 mg/kg in their drinking water ad libitum) and nimodipine (3 and 12 mg/kg in their food ad libitum). After weaning, pups were exposed until the 60th day of age to the same treatment as their mothers were. Afterwards, pups from the 60th to 90th day of age were fed with a normal diet. In 30-, 60-, and 90-day-old conscious and anaesthetized pups, we evaluated the following: 1) systolic arterial blood pressure; 2) vasomotor responses elicited by various agents: L-noradrenaline (0.1, 1, and 5 micrograms/kg IV), L-isoprenaline (0.01, 0.1, and 1 micrograms/kg IV), and acetylcholine (0.01, 0.1, and 1 micrograms/kg IV) and by sinus-carotid baroreceptor stimulation; and 3) catecholamine, acetylcholinesterase, and adenosinase plasma levels. Prenatal and postnatal exposure to Ca2+-antagonist drugs significantly (P less than .05) decreased the pressor response to sinus-carotid baroreceptor stimulation and to L-noradrenaline and increased the hypotensive responses to L-isoprenaline and acetylcholine. Moreover, this type of treatment, although it induced a significant (P less than .05) decrease of catecholamine plasma levels, did not modify the acetylcholinesterase and adenosinase plasma levels in 30- and 60-day-old rats. On the 90th day of age, the evaluated parameters were not different from those of control rats. Our results showed that exposure to Ca2+ antagonists during pregnancy and the postnatal period may alter the functional development of rat vasomotor reactivity.

Acetylcholinesterase↗
PubMed1989

Research on heterocyclic compounds. XXV. Phenyl derivatives of fused imidazole systems: antiinflammatory activity.

A group of seven acidic phenyl derivatives of some fused imidazole systems were subjected to a series of tests in vivo in order to evaluate their pharmacological activity. Antiinflammatory activity was studied by means of the carrageenin-induced rat paw edema. Hot plate test and writhing induced by acetic acid in mice were used to evaluate analgesic activity. Yeast-induced hyperthermia in rats was employed to study antipyretic action. Irritative and ulcerogenic action on the rat gastric mucosa was examined at higher doses. The antiaggregating activity and the inhibition of platelet malondialdehyde production were studied in vitro. All experimental results are discussed from the point of view of structure-activity relationships and mode of action.

Animals↗
PubMed1988

Prenatal and postnatal thallium exposure in rats: effect on development of vasomotor reactivity in pups.

Vasomotor reactivity has been evaluated in rats exposed perinatally and postnatally to thallium sulphate (1 mg/dl in their drinking water ad libitum). Prenatal and postnatal exposure to thallium did not modify the values of the systolic arterial blood pressure on the 30th and 60th day in pups of normotensive and DOCA-hypertensive rats. The hypertensive responses induced by endosinusal carotid hypotension and by 1-noradrenaline in pups of normotensive and DOCA-hypertensive rats, exposed or not exposed to thallium sulphate, were more intensive on the 60th than on the 30th day. Similar effects were observed for the hypotensive responses induced by 1-isoprenaline and acetylcholine. Prenatal exposure to thallium did not modify hypertensive responses induced by endosinusal carotid hypotension on the 30th and 60th days, but it caused a decrease of hypertensive responses induced by 1-noradrenaline on the 30th and 60th days and hypotensive responses induced by 1-isoprenaline and acetylcholine exclusively on the 60th day. Postnatal exposure to thallium did not modify hypertensive responses induced by endosinusal carotid hypotension and hypotensive responses induced by acetylcholine, but it caused a decrease of hypertensive responses induced by 1-noradrenaline on the 30th and 60th days in pups of normotensive rats and exclusively on the 60th day in pups of DOCA-hypertensive rats. Moreover, postnatal exposure to thallium caused a decrease of the hypotensive response induced by 1-isoprenaline exclusively on the 60th day. Our findings show that prenatal and postnatal exposure to thallium sulphate modifies the rat's developing vascular autonomic nervous system with a reduction of the alpha, beta-adrenergic and muscarinic vasomotor reactivity.

Animals↗
PubMed1988

Glutamergic transmission and cardiovascular apparatus in normotensive rats.

The cardiovascular effects induced by L-glutamic acid (G) on the cardiovascular apparatus of normotensive ethyl urethane-anaesthetized rats have been evaluated. (a) When administered i.v. (1 to 100 mg/kg) G induced a transitory and dose-dependent increase of arterial pressure (AP) with very moderate sinus bradycardia. It was antagonized by L-glutamic acid diethyl ester (GDEE, 0.1 to 100 mg/kg i.v.). (b) The intracerebroventricular (i.c.v.) administration of G (third ventricle, right lateral ventricle, posterior hypothalamus and striatum) at a dose of 0.1 to 10 mg/an induced a transitory and dose-dependent increase of AP, abolished by i.c.v. GDEE (1 to 10 mcg/an). (c) G hypertension was reduced by several procedures, i.e. catecholamine depletion, alpha 1, alpha 1 and alpha 2 or beta adrenergic blocks, alpha 2 central adrenergic stimulation, Ca2+ transmembrane or gangliary block, surrenectomy, and spinal transection at C7. (d) Atropine, bilateral vagotomy and sinus carotidal denervation increased G hypertension. (e) Therefore the bradycardia does seem to be due to a reflex-mediated effect via sinus carotid and aortic baroreceptors. (f) These data show that glutamergic transmission also participates through a central mechanism in the regulation of cardiovascular function in rats, via an increase in central sympathetic efferent activity.

Animals↗
PubMed1988

Research on heterocyclic compounds. XXIV. Antiinflammatory activity of some imidazo[1,2-c]pyrimidine derivatives.

A group of four acidic imidazo[1,2-c]pyrimidine derivatives were subjected to a series of tests in vivo in order to assess their pharmacological activity. Antiinflammatory activity was studied by means of the carrageenin-induced paw edema and pleurisy in rats. Hot plate test and writhing induced by acetic acid in mice were employed to evaluate analgesic activity, whereas the yeast-induced hyperthermia in rats was used to study antipyretic activity. The irritative and ulcerogenic action on the rat gastric mucosa was examined at higher doses. The inhibitory activity on the platelet malondialdehyde production was studied in order to obtain information about the mechanism of action of test compounds.

Acetates↗
PubMed1987

Central and peripheral cardiovascular effects of beta-endorphin in normotensive and spontaneously hypertensive rats and in rats rendered hypertensive by deoxycorticosterone acetate administration.

The cardiovascular effects of beta-endorphin [beta-LPH-(61-91)] were investigated after systemic (i.v.) and central (third ventricle and right lateral ventricle) administration in urethane-anesthetized rats. beta-Endorphin (10 and 100 micrograms/kg i.v. or 40 micrograms into the third ventricle or into the lateral ventricle) in normotensive animals induced a decrease in blood pressure and bradycardia. The same dose of beta-endorphin by systemic and central administration induced much more pronounced cardiovascular effects in spontaneously hypertensive rats and in rats rendered hypertensive by DOCA administration than in normotensive rats. Naloxone i.v. pretreatment reduced the cardiovascular effects induced by beta-endorphin.

Animals↗
PubMed1987

Research on heterocyclic compounds. XXII. Imidazo[1,2-a]pyrimidines.

We have taken into consideration a group of 21 imidazo [1,2-a]pyrimidine derivatives, some of which were already known, whereas the others were synthesized and characterized by us to complete the series. Antiinflammatory, analgesic, antipyretic and ulcerogenic activities of such compounds were evaluated in comparison with indomethacin, in order to get useful information about structure-activity relationships.

Animals↗
PubMed1987

Esters of N-methyl-N-(2-hydroxyethyl or 3-hydroxypropyl)-1,3,3-trimethylbicyclo [2.2.1]heptan-2-endo-amine with hypotensive activity.

The synthesis of title compounds by reaction of fenchone nitrimine with 2-aminoethanol and 3-aminopropanol, followed by stereospecific NaBH4 reduction of the resulting imines, Eschweiler-Clarke reductive methylation and esterification with aliphatic and aromatic acyl chlorides is described. Some esters showed an appreciable hypotensive activity in rats. Effects on heart rate and antiarrhythmic activity in rats, as well as infiltration anesthesia in mice, are also reported.

Anesthetics, Local↗
PubMed1986

Effect of Salmonella typhimurium porins on the cardiovascular and renal apparatus.

The cardiovascular effects of porins were evaluated using porins isolated from Salmonella typhimurium SH5014. In dogs porins depress arterial systemic pressure, vasomotor reactivity of norepinephrine and peripheral vagal stimulation. They are capable of modifying the sinocarotidal baroreceptor reactivity. In mice porins increase the cardiotoxic effects of isoprenaline, thyroxine, emetine and of p-nitrophenol. In rats porins increase the arrhythmogenic and lethal effects of BaCl2 and also give rise to renal lesions, probably at the tubular level.

Animals↗