Vertebrate melanophores as potential model for drug discovery and development: A review

Abstract

Drug discovery in skin pharmacotherapy is an enormous, continually expanding field. Researchers are developing novel and sensitive pharmaceutical products and drugs that target specific receptors to elicit concerted and appropriate responses. The pigment-bearing cells called melanophores have a significant contribution to make in this field. Melanophores, which contain the dark brown or black pigment melanin, constitute an important class of chromatophores. They are highly specialized in the bidirectional and coordinated translocation of pigment granules when given an appropriate stimulus. The pigment granules can be stimulated to undergo rapid dispersion throughout the melanophores, making the cell appear dark, or to aggregate at the center, making the cell appear light. The major signals involved in pigment transport within the melanophores are dependent on a special class of cell surface receptors called G-protein-coupled receptors (GPCRs). Many of these receptors of adrenaline, acetylcholine, histamine, serotonin, endothelin and melatonin have been found on melanophores. They are believed to have clinical relevance to skin-related ailments and therefore have become targets for high throughput screening projects. The selective screening of these receptors requires the recognition of particular ligands, agonists and antagonists and the characterization of their effects on pigment motility within the cells. The mechanism of skin pigmentation is incredibly intricate, but it would be a considerable step forward to unravel its underlying physiological mechanism. This would provide an experimental basis for new pharmacotherapies for dermatological anomalies.

Towards a Comprehensive Catalog of Zebrafish Behavior 1.0 and Beyond

“…), a part of social behavior (e.g., display, fight or courtship), 42 as well as a result of stress/sickness, or drug-evoked dispersion (skin darkening) or aggregation (paling) of melanophores. 85 Specific drugs (e.g., alcohol, ibogaine 86,87 ) evoke robust skin darkening in adult zebrafish, while some factors (e.g., cold exposure, pathogens) can evoke paling (e.g., sickness behavior). Coloration response can be assessed manually (by visual inspection) or using automated (luminescence-based) tools.…”

Introduction

“…Under in vitro conditions, serotonin exerted variable effects on skin cells depending on the context (Nordlind et al, 2008, Salim and Ali, 2011, Slominski et al, 2005c). It stimulated proliferation of dermal fibroblasts (Slominski et al, 2005c), similarly to non-skin fibroblasts (Seuwen et al, 1988; Seuwen and Pouyssegur, 1990; David, 1991; Nebigil et al, 2000).…”

Comparative light and electron microscopic studies of dorsal skin melanophores of Indian toad, Bufo melanostictus

“…Receptor systems participate in a very coordinated manner in mediation of these responses of color change [11]. Due to this dynamic property and availability of multiple receptor-ligand binding sites on melanophores, they are excellent targets for understanding the effects of various pharmacological agents [12][13][14]. However, ultrastructural details of lower vertebrate melanophores are still wanting.…”