Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PRD-92-Ea [5,5-Dimethyl-11-oxo-5H, 11H-(2) benzopyrano (4,3-g) (1) benzopyran-9-carboxylic acid ethanolamine], was an active antiallergic compound in rat and monkey experimental models of immediate hypersensitivity. It inhibited, in a dose-dependent manner, the rat PCA reaction after both intravenous and oral administration. It also inhibited the degranulation of rat peritoneal mast cells after antigenic challenge. PRD-92-Ea was also active in preventing bronchoconstriction in Ascaris-sensitive Rhesus monkeys after intravenous, topical and oral administration. Using chopped monkey tissues, it was found that PRD-92-Ea prevented histamine release from the respiratory mast cells, but not from the cutaneous mast cells. No reason for this dichotomy of effect is known. PRD-92-Ea showed antagonistic activity against the allergic mediators released from mast cells. In order of decreasing potency it was active against SRS-A (monkey lung), PGF2alpha, PGE2, serotonin, bradykinin and histamine. Apart from its antiallergic effects PRD-92-Ea had no other significant pharmacological activity.
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PMID:Pharmacologic profile of a new antiallergic compound PRD-92-Ea. 7 14

Three new antiallergic drugs, Doxantrazole, PRD-92 and N5', as well as disodium cromoglycate, inhibited the IgE-mediated PCA reaction in the rat triggered by the homologous antigen, but did not have an antagonistic effect on histamine itself. Moreover, all the drugs examined caused in vitro inhibition of antigen-mediated histamine release from peritoneal mast cells and chopped lung tissue of sensitized rats producing IgE antibodies. Doxantrazole had a synergistic effect on the inhibition of histamine release by isoproterenol, whereas the other drugs were devoid of this capacity. PRD-92 and N5' inhibited the ionophore A23,187 induced histamine release, but did not have any effect on the D2O-enhanced histamine release which was triggered by antigen.
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PMID:The inhibition of histamine release by antiallergic drugs. 7 49

DSCG and PRD-92-Ea showed tachyphylaxis in the rat PCA test when a large intravenous dose (40 mg/kg of DSCG and 20 mg/kg of PRD-92-Ea) was given 30 min before administering intravenously the expected effective doses at the time of antigen challenge. This predosing led to a marked loss of effectiveness. Cross-reacting tachyphylaxis was also demonstrated in this model. Predosing rats with DSCG led to a great loss of effectiveness of a subsequent expected active dose of PRD-92-Ea and predosing with PRD-92-Ea had the same effect in preventing the antiallergic action of a subsequent dose of DSCG. The Rhesus monkey (Macaca mulatta) did not exhibit this phenomenon of tachyphylaxis. PRD-92-Ea and DSCG were given intravenously 30 min before and the same dose of 20 mg/kg repeated just before Ascaris suum challenge in the Rhesus monkey asthma model with no loss of their expected effectiveness.
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PMID:The difference in effect of predosing with antiallergic compounds between the rat PCA model and the monkey asthma model. Comparison of the effects of PRD-92-Ea and disodium cromoglycate. 41 94

The effects of PRD-92 Ea were examined on the increased plasma protein extravasation in the skin of guinea pig and rat elicited by specific antigens and spasmogenic mediators. PRD-92 Ea was found to be a potent inhibitor of rat PCA reactions when administered intradermally, intravenously or orally. This compound did not antagonize the local inflammatory responses of histamine, bradykinin or 5HT. This implies that in vivo PRD-92 Ea acts predominantly as an anti-allergy agent rather than a spasmogen antagonist. At high concentrations PRD-92 Ea directly increased vascular permeability when injected intradermally (greater than 250 micrograms/site) or administered by aerosol into the lung (greater than 10%). The importance of investigating such direct irritant actions of similar new drugs is discussed.
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PMID:Anti-allergy properties of PRD-92 Ea in guinea pig and rat. 644 26

Ro 21-7634 was examined for oral antiallergic activity in two in vivo models commonly used to evaluate antiallergics. In the rat PCA test, this drug had an oral ID50 of 1.14 mg/kg and was found to be more potent than several other antiallergics including Disodium Cromoglycate (cromoglycate), Oxatomide, Doxanthrazole, Xanoxate, 2,6-bis (ethyoxyoxalylamino) pyridine, PRD-92-EA and M + B 22,948. In contrast to cromoglycate, Ro 21-7634 was found to be an orally active inhibitor of antigen-induced broncho-constriction in passively sensitized rats (ID50 = 0.2 mg/kg). In addition, Ro 21-7634 inhibited antigen-induced histamine release in an in vivo passive peritoneal anaphylaxis test system, following intraperitoneal administration. Ro 21-7634 demonstrated no end organ antagonism toward histamine, metacholine or serotonin in the guinea pig.
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PMID:Ro 21-7634, a new antiallergic agent with potent oral activity. 702 96