RESUMO
In previous work, we demonstrated that dehydroleucodine (DhL), a lactone isolated from Artemisia douglasiana Besser, prevents gastroduodenal damage induced by absolute ethanol (EtOH). The present study examined the effects of DhL - applied alone or before EtOH - on gastroduodenal cells containing 5-hydroxytryptamine (5-HT), to clarify the mechanism of action of the drug. Mice were divided into four groups: (I) control; (II) DhL; (III) EtOH, and (IV) DhL + EtOH. Stomachs and duodena were studied by immunohistochemistry and image analysis. EtOH decreased the immunopositive cell number and the area occupied by these cells. This effect was prevented by DhL. DhL alone did not affect the gastric immunopositive cell number and area. Duodena treated only with DhL exhibited a reduction of immunopositive cell number, but no change in area was observed. We propose that the drug probably inhibits the release of the inflammatory mediator 5-HT from endocrine cells, acting as a 'cell stabilizer' in response to injury.
Assuntos
Antiulcerosos/farmacologia , Duodeno/citologia , Duodeno/efeitos dos fármacos , Lactonas/farmacologia , Serotonina/metabolismo , Sesquiterpenos/farmacologia , Estômago/citologia , Estômago/efeitos dos fármacos , Animais , Contagem de Células , Tamanho Celular , Interações Medicamentosas , Células Enterocromafins/citologia , Células Enterocromafins/efeitos dos fármacos , Etanol/administração & dosagem , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Masculino , Camundongos , Camundongos EndogâmicosRESUMO
In this work we have demonstrated the influence of a short chain fatty acid (acetate) on the number of enterochromaffin (EC) cells containing serotonin (5HT), at two different pH (pH 6.9 absorptive stimuli, and pH 2.9 secretory stimuli), infused into the colon during one hour. The number of EC cells decrease significatively, specially in the cecum with a solution of low pH (2.9). The action of piprenzepine in preventing this reduction demonstrated that was partly mediated by a cholinergic receptor mechanism. On the other hand, a decrease on the release of 5HT to the lumen was a observed under the influence of pirenzepine. We conclude that the short chain fatty acid acetate, at a low pH induces the release of serotonin through a cholinergic mechanisms indicated by the inhibition observed with antimuscarinic drug.
Assuntos
Colo/metabolismo , Ácidos Graxos Voláteis/farmacologia , Pirenzepina/farmacologia , Serotonina/metabolismo , Acetatos/farmacologia , Ácido Acético , Animais , Ceco/citologia , Ceco/efeitos dos fármacos , Ceco/metabolismo , Colo/citologia , Colo/efeitos dos fármacos , Células Enterocromafins/efeitos dos fármacos , Células Enterocromafins/metabolismo , Concentração de Íons de Hidrogênio , Infusões Intravenosas , Mucosa Intestinal/citologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
En este trabajo hemos la influencia de un ácido graso de cadena corta (acetato) sobre el número de células enterocromafines (EC) conteniendo serotonina (5HT) a dos diferentes pH (pH 6.9, estímulo absortivo y pH 2.9 estímulo secretor) infundido durante una hora en el colon. El número de células EC disminuye significativament con una solución infundida a pH 2.9, especialmente en el ciego. La acción de la pirencepina en prevenir esta reducción demuestra que el mecanismo se efectúa parcialmente a través de receptores colinérgicos. Por parte, se observa una disminución de la liberación de 5HT, a través de un mecanismo colinérgico, como lo indica la inhibición observada con la droga antimuscarínica (AU)
Assuntos
Animais , Masculino , Ratos , Pirenzepina/farmacologia , Colo/citologia , Serotonina/metabolismo , Ácidos Graxos Voláteis/farmacologia , Colo/efeitos dos fármacos , Colo/metabolismo , Acetatos/farmacologia , Células Enterocromafins/efeitos dos fármacos , Células Enterocromafins/metabolismo , Ceco/citologia , Ceco/efeitos dos fármacos , Ceco/metabolismo , Mucosa Intestinal/citologia , Infusões Intravenosas , Concentração de Íons de Hidrogênio , Ratos Sprague-DawleyRESUMO
The possibility that VIP (Vasoactive intestinal peptide) could influence the enterochromaffin (EC) cell secretion of serotonin (5HT) and the action of VIP on the mast cell population of lamina propria were investigated in Wistar rat colon infused with a short chain fatty acid solution (sodium acetate), during a 1 h period. Under the action of an intravenous injection of synthetic porcine VIP, 14 micrograms/kg/h), the number of EC cells diminished significantly in the cecum and left colon, when compared to non-injected animals, both infused with a sodium acetate solution. At the same time, the number of mucosal mast cells in the crypts and lamina propria decreased significantly in the cecum. The postulate we put forward is that these VIP-induced changes are exerted through the stimulation of 5HT released from EC cells not only under normal physiological conditions but probably also under pathological conditions.