Melanophores in Damselfish Neurofibromatosis: Alterations in Morphology and Melanosome Aggregation Responses

Abstract

Abstract Damselfish neurofibromatosis (DNF) is a neoplastic disease affecting bicolor damselfish Pornacentrus partitus on south Florida reefs. This disease exhibits many traits in common with neurofibromatosis type-1 in humans, including multiple plexiform neurofibromas and areas of hyperpigmentation. An important issue in understanding the pathogenesis of DNF is the relation between chromatophores and other cell types that give rise to tumors in this disease. Melanophores cultured from tumors of fish with DNF were compared in vitro with cells from normal skin of healthy fish to determine if these cells were morphologically or physiologically altered in this disease. Melanophores from tumors were significantly larger in cross-sectional perimeter and area than normal counterparts. Pigment translocation responses were measured by bath application of norepinephrine. At drug concentrations of 5 × 10-9 to 5 × 10-5 M, significantly fewer tumorderived cells than normal cells exhibited complete melanosome aggrega...