RESUMO
The present study involves the analysis of structural, ultrastructural and biochemical modifications induced by colchicine (Col) in Guinea Pig parotid gland. The biochemical studies showed that the highest concentration of soluble proteins occurred 4 hs after colchicine injection. The curve of a-amylase activity in the gland showed an increase in enzyme activity over control at approximately 4 hs post-injection. At 8 hours the rise was even greater. The structural and ultrastructural analyses of the gland revealed that 4 hs post-injection colchicine exerts its maximum inhibitory effect on secretion. At this treatment time, the cytoplasm contained granules of various sizes and sharp outlines. Large areas of the cytoplasm exhibited material which resembled the granular content and seemed to result from the fusion of granules. No secretion was found in the lumen of the ducts. The inhibitory effect on secretion would be due to the disassembly of microtubules which would in turn impair transport of the granules to the apical surface of the membrane and eventual exocytosis. We herein propose that the effects of colchicine in the experimental conditions of this study would be largely reversible at 24 hours. At this time, structural, ultrastructural and biochemical features were similar to those of controls.
