Resumo

HEBLING, André; ESQUISATTO, Marcelo Augusto M.  e  CASTRO, Heloisa A. de Lima. Histochemical Study of Enzyme in Frontal Muscle of Norfolk Rabbit (Oryctolagus cuniculus). Int. J. Morphol. [online]. 2006, vol.24, n.2, pp. 151-154. ISSN 0717-9502.  doi: 10.4067/S0717-95022006000300004.

The human frontal muscles has two bellies, forming, together with the occipital muscle and the aponeurotic galea, the occipitofrontal muscle. Being a striated skeletal muscle, the frontal muscle can show muscular fibers with high intensity oxidation (type I) and with low intensity oxidation (type II). A histochemical process using organic and inorganic chemical reactions allows us to obtain a product that is visible through optical microscopy. The purpose of this paper is to determine, by means of the histochemical process of the Nicotinamide Adenine Dinucleotide Tetra-zolium Reductase (NADH-TR) reaction the distribution of the number of the type I and II frontal muscle fibers of female, six to eight months old, 2.8 to 3.1 Kg English Norfolk rabbits. In 1010 fibers studied, we found 33.8% type I, 17.4% type IIA and 48.8% type IIB. The majority of fibers were type II, demonstrating this muscle's intense activity during facial mimicking. Type II fibers showed a reduced oxidative intensity, which made them subject to muscular fatigue. These findings may be of help in the study to understanding the pathological process that may occur in this muscle

Palavras-chave : Histochemistry; Frontal muscle; Fiber types.