HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology



Different putative neuromodulators are present in the nerves which distribute to the teleost skeletal muscle

G. Radaelli1, C. Domeneghini,2 S. Arrighi2, F. Mascarello1, A. Veggetti3

1Department of Animal Sciences, Faculty of Veterinary Medicine, University of Padova, 2Institute of Domestic Animal Anatomy, Faculty of Veterinary Medicine, University of Milano, 3Department of Veterinary Morphophysiology and Animal Production, Faculty of Veterinary Medicine, University of Bologna, Italy

Offprint requests to: Prof. Cinzia Domeneghini, Istituto di Anatomia degli Animali Domestici, Via Celoria, 10, I-20133 Milano, Italy. Fax: 02.2367788

 

Summary. The presence of putative neuromodulators in the nerve fibres was investigated in white skeletal muscle of two teleost fish not taxonomically correlated and showing different patterns of innervation (multiple versus focal innervation). Cryostat sections of epaxial, hypaxial and adductor mandibulae (AM) muscles of Sparus aurata and Anguilla anguilla were stained histochemically for reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase. Other sections were used for indirect immunohistochemistry (streptavidin-biotin and rhodamine immunofluorescence methods), employing antibodies specific for putative excitatory or inhibitory peptides, including CGRP, substance P, met-enkephalin, bombesin, and VIP. In addition, ultrastructural observations were performed in order to describe the morphology of the motor endplates. A strong immunoreactivity for CGRP and substance P was found in many nerve terminals. Met-enkephalin, bombesin and VIP immunoreactivities were less frequently observed. No immunoreactivity was observed to CCK, NPY or 5-HT. NADPH-diaphorase was identified in nerve fibres of the AM complex only of A. anguilla. Electron microscopy observations evidenced more than one type of synaptic vesicle in motor endplates. Some differences in putative neuromodulator distributions were observed in the two species and muscle complexes, which may be related to the different taxonomical position as well as the different pattern of innervation of white muscle fibres. Histol. Histopathol. 13, 939-947 (1998)

 

Key words: Teleosts, skeletal muscle, neuropeptides, NOS.

DOI: 10.14670/HH-13.939