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Biomedical subjects

F Berti

Publications and source records attributed to F Berti.

At least 145 records · Page 8Linked to original sources
PubMed1982

Anticholinergic agents prevent guinea-pig airway constriction induced by histamine, bradykinin and leukotriene C4: Relationship to circulating TXA2.

Various doses of histamine, bradykinin and leukotriene C4 caused bronchoconstriction in anaesthetized guinea-pigs which were breathing spontaneously or artificially ventilated; there was a simultaneous, dose-related increase in circulating TXA2. The animals were prepared for continuous recording of extracorporeal circulation in order to detect the appearance in the blood of bioassayable levels of TXA2 -like substance. Furthermore, a TXA2 derivative, the mono-O-Me-TXB2, was radioimmunoassayed. Atropine, oxytropium bromide and ipratropium bromide given in mumol doses prevented both the increased airway resistance and the release of TXA2-like substance in the blood Pirenzepine dihydrochloride was the least active of the drugs tested. The protecting activity of anticholinergics and the relationship with their ability to affect TXA2-like substance generation suggest a new site of action for these drugs besides the blockade of muscarinic receptors.

Airway Resistance↗
PubMed1982

Desensitization of beta-adrenoreceptors in guinea-pig trachea: a prostaglandin mediated phenomenon.

1 The formation and release of PGE2-like material (PGE2-lm) from guinea-pig isolated trachea and human bronchi following relaxation with isoprenaline (I) was investigated. 2 When airway smooth muscle precontracted with pilocarpine is relaxed by I, PGE2-lm is released in the bathing fluid. Under conditions of beta-adrenoreceptor desensitization, a greater amount of PGE2-lm is formed and the responsiveness of guinea-pig tracheal spirals to cumulative doses of I is diminished. 3 Inhibition of cyclo-oxygenase with indomethacin does not modify the relaxation induced by I but prevents the occurrence of refractoriness to I as well as formation and release of PGE2-lm. Addition of exogenous PGE2 to guinea-pig tracheas which were treated with indomethacin is able to restore the capacity of I to cause tachyphylaxis. 4 It is concluded that PGE2 which does not mediate the relaxation induced by I in airway smooth muscle, is responsible for the onset of desensitization of the beta-adrenoreceptor.

Animals↗
PubMed1982

New pharmacological aspects on the antiasthmatic activity of tiaramide-HCl.

Tiaramide hydrochloride (THC) is a benzothiazoline derivative with a remarkable antianaphylactic activity: in anaesthetized guinea-pig it shows protecting effects against histamine (H)- and bradykinin (Bk)-induced bronchoconstriction, preventing increase of lung resistance and decrease of dynamic compliance. At the same time THC inhibits formation of circulating thromboxane A2 brought about by H and Bk. THC is also able to antagonize the contractions induced by CaCl2 on isolated guinea-pig tracheal spirals and its mode of action seems to be of the competitive type. Furthermore THC abolishes the "tonic" phase of K+-induced contractions of guinea-pig taenia coli which are dependent on inward movement of calcium, whereas the "phasic" component of the contractions is left unaltered. THC is a very weak inhibitor of 3'-5' cyclic adenosine monophosphate phosphodiesterase which is affected only at very high dosage (10(-2) M). The calcium antagonistic activity of THC may explain both its bronchodilating and antianaphylactic properties.

Anaphylaxis↗
PubMed1981

beta-Adrenoceptor activation induces prostaglandin E2 generation in guinea-pig trachea.

Isoproterenol and salbutamol caused relaxation of guinea-pig trachea, and generation of PGE2. The phenomenon appears to be specific for beta-adrenergic agonists since the relaxant activity induced by atropine, theophylline and papaverine was not associated with generation of prostaglandin-like material from tracheal smooth muscles. Indomethacin reduced only slightly the relaxation of the tracheal tissue induced by isoproterenol and salbutamol. The possibility is discussed that the increased arachidonic acid metabolism during trachea beta-adrenergic relaxation represents a metabolic event involving phospholipid methylation and membrane fluidity.

Albuterol↗
PubMed1981

Prostacyclin (PGI2) generation in lungs of fetal and newborn rabbit.

Perfused lungs from fetal (26-28 days of gestation) and newborn rabbits preferentially transform arachidonic acid into a substance which mimics PGI2 activity on different isolated tissues in cascase. These data support the hypothesis that antiplatelet and vasodilating vasodilating activity of PGI2 generated in the lungs may contribute to the characteristics of the fetal circulation.

Animals↗
PubMed1980

Bronchoconstriction by histamine and bradykinin in guinea pigs: relationship to thromboxane A2 generation and the effect of aspirin.

Histamine 2.5, 5, 10 or 20 microgram/kg i.v. induce a pronounced bronchospasm in guinea-pigs, accompanied by a dose-related increase of TXA2 in arterial blood, as revealed by contraction of rabbit isolated aorta and by radioimmunoassay. Aspirin 10 mg/kg prevented formation of TXA2-like material without significantly modifying the severity of the bronchospasm. Bradykinin 0.5, 1 or 2 microgram/kg i.v. acted similarly, except that pretreatment with aspirin blocked both the increased airway resistance and release of TXA2. Aspirin also blocked the increase in blood pressure and heart rate caused by histamine or bradykinin.

Acetylcholine↗
PubMed1980

Atropine inhibits thromboxane A2 generation in isolated lungs of the guinea-pig.

1 Histamine (0.5 to 5 micrograms) and slow reacting substance of anaphylaxis (SRS-A, 0.05 to 0.3 u), injected in the isolated, perfused lungs of normal and ovalbumin-sensitized guinea-pigs, promote formation and release of thromboxane A2(TXA2) and other arachidonate metabolites, the effect being more pronounced in sensitized lungs. 2 Carbachol injected (1 to 10 micrograms) or perfused (1 micrograms ml-1 min-1) through normal or sensitized lungs does not elicit formation of TXA2 and prostaglandins. Furthermore the increased generation of arachidonate metabolites due to histamine is not altered by carbachol. 3 Atropine and ipratropium bromide (1 microgram ml-1 min-1) reduce significantly the increased rate of production of TXA2 caused by histamine and SRS-A both in normal and sensitized lungs, whereas hexamethonium (10 to 25 micrograms ml-1 min-1) is ineffective. 4 The mechanism of action of atropine in inhibiting the increased generation of TXA2 is clearly not related to its antimuscarinic or antihistaminic properties. The drug might act at the early events, involved in the activation of arachidonic acid metabolism. The results suggest new sites of action for atropine which, besides the control of the vagal bronchomotor tone, interferes directly with the primary mediators of anaphylaxis.

Animals↗
PubMed1979

Prostacyclin (PGI2) in pregnant human uterus.

Prostacyclin lowers the tonus and reduces the spontaneous motility of isolated pregnant human myometrium. This effect seems to be related to coclic-AMP accumulation, since PGI2 increases the formation of this cyclic nucleotide in incubated minces of pregnant and non-pregnant uterus. The ability of this tissue to generate a labile substance which inhibits platelets aggregation, has been demonstrated and discussed.

Adult↗