SciELO - Scientific Electronic Library Online

 
vol.37 issue7The interaction of housing condition and acute immobilization stress on the elevated plus-maze behaviors of protein-malnourished ratsSelegiline increases heme oxygenase-1 expression and the cytotoxicity produced by dopamine treatment of neuroblastoma SK-N-SH cells author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Brazilian Journal of Medical and Biological Research

On-line version ISSN 1414-431X

Abstract

FACCIONI-HEUSER, M.C.; ZANCAN, D.M.  and  ACHAVAL, M.. Monoamines in the pedal plexus of the land snail Megalobulimus oblongus (Gastropoda, Pulmonata). Braz J Med Biol Res [online]. 2004, vol.37, n.7, pp. 1043-1053. ISSN 1414-431X.  http://dx.doi.org/10.1590/S0100-879X2004000700014.

In molluscs, the number of peripheral neurons far exceeds those found in the central nervous system. Although previous studies on the morphology of the peripheral nervous system exist, details of its organization remain unknown. Moreover, the foot of the terrestrial species has been studied less than that of the aquatic species. As this knowledge is essential for our experimental model, the pulmonate gastropod Megalobulimus oblongus, the aim of the present study was to investigate monoamines in the pedal plexus of this snail using two procedures: glyoxylic acid histofluorescence to identify monoaminergic structures, and the unlabeled antibody peroxidase anti-peroxidase method using antiserum to detect the serotonergic component of the plexus. Adult land snails weighing 48-80 g, obtained from the counties of Barra do Ribeiro and Charqueadas (RS, Brazil), were utilized. Monoaminergic fibers were detected throughout the pedal musculature. Blue fluorescence (catecholamines, probably dopamine) was observed in nerve branches, pedal and subepithelial plexuses, and in the pedal muscle cells. Yellow fluorescence (serotonin) was only observed in thick nerves and in muscle cells. However, when immunohistochemical methods were used, serotonergic fibers were detected in the pedal nerve branches, the pedal and subepithelial plexuses, the basal and lateral zones of the ventral integument epithelial cells, in the pedal ganglion neurons and beneath the ventral epithelium. These findings suggest catecholaminergic and serotonergic involvement in locomotion and modulation of both the pedal ganglion interneurons and sensory information. Knowledge of monoaminergic distribution in this snail´s foot is important for understanding the pharmacological control of reflexive responses and locomotive behavior.

Keywords : Pedal plexus; Catecholamines; Serotonin; Glyoxylic acid; Immunohistochemistry; Gastropod.

        · text in English     · pdf in English