Published June 1979 | Version v1
Report Open

Studies on the increase of capillary permeability in rat skin under the action of pyridoxal 5' phosphate

Description

The activity of pyridoxal 5'-phosphate (PLP) is described on the vascular permeability response, measured in the abdominal wall of rats from the amount of extravased Evans blue labelled with radioactive iodine 125 or 131. The PLP effect is related to histamine release as it has been showed by tha use of antihistaminics. An attempt has been made in order to correlate structure and biological activity by using PLP analogs. The intact molecule of PLP seems to be the proper active substance. The critical role of calcium in histamine release is discussed in relation to our observations. In the presence of high concentrations of calcium and lantanium, PLP fails to increase the vascular permeability; magnesium does not show any influence. The calcium mobilization produced by theophylline results in inhibition of the response. The course of the reaction between PLP and histamine in vitro was followed; the synthetic cyclic product is deprived of activity and does not interfere with the intrinsic effects of PLP and histamine. (Author)

Availability note (English)

MF available from INIS under the Report Number.

Abstract (Portuguese)

Descreve-se a atividade do piridoxal 5'-fosfato (PLP) em aumentar a permeabilidade capilar, medida na pele de rato pelo extravasamento do azul de Evans marcado com o iodo radioativo (125I ou 131I). O efeito do PLP decorre essencialmente da liberacao de histamina dada a inibicao do fenomeno com o uso de anti-histaminicos. Entre varios analogos de PLP experimentados com a intencao de se estabelecer relacao entre estrutura e atividade biologica, permanece a molecula intacta de PLP como aquela que preenche os requisitos de substancia ativa. Discute-se o papel critico de calcio na liberacao de histamina em relacao com as nossas observacoes. A adicao de altas concentracoes de calcio e lantanio provoca o bloqueio do efeito do PLP; magnesio, entretanto, nao tem influencia. A mobilizacao de calcio produzida por teofilina resulta tambem na inibicao da manifestacao da resposta. O curso da reacao entre PLP e histamina que leva a formacao de um produto ciclico foi seguido in vitro. Esse complexo, destituido de atividade sobre o aumento da permeabilidade capilar, nao provoca efeitos inibitorios das atividades intrinsecas de PLP e histamina. (Autor)

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Additional details

Additional titles

Original title (Portuguese)
Estudos sobre o aumento da permeabilidade capilar na pele de rato por acao do piridoxal 5'-fosfato

Publishing Information

Imprint Pagination
39 p.
Journal Issue
no. 137
Series
IEA Dissertacao e Tese.
Report number
IEA-DT--137