Effects of GABA-ergic agonists and antagonists were examined on the melanophores of a carp C. mrigala in vitro. GABA and baclofen both induced concentration - related dispersion in fish melanophores. Denervation of the melanophores by reserpine treatment potentiated the sensitivity of the melanophores to GABA. While denervation by cooling treatment inhibited the sensitivity of the melanophores ...

Zidovudine (AZT) induced concentration related aggregation in C. mrigala melanophores. Denervated melanophores failed to respond to AZT. Specific and nonspecific alpha adrenoceptor antagonists completely blocked the responses of fish melanophores to AZT. Histamine and prostaglandin antagonists also inhibited aggregation of the melanophores induced by AZT. The results suggest that AZT may releas...

introduction: effects of melatonin (mt) were comparatively examined on melanophores of isolated skin in adults and tadpole’s tailfin of a frog rana cyanophlyctis. mt is generally considered as a potent melanophores aggregating hormone besides regulating the sleep wake cycle in vertebrates. methods: melanophore size index (msi) was chosen as a recording parameter of the responses. concentration-...

Introduction: Effects of melatonin (MT) were comparatively examined on melanophores of isolated skin in adults and tadpole’s tailfin of a frog Rana cyanophlyctis. MT is generally considered as a potent melanophores aggregating hormone besides regulating the sleep wake cycle in vertebrates. Methods: Melanophore size index (MSI) was chosen as a recording parameter of the responses. Concentr...

Animal skin pattern is one of the good model systems used to study the mechanism of pattern formation. Molecular genetic studies with zebrafish have shown that pigment cells play a major role in the mechanism of stripe formation. Among the variety of cellular events that may be involved in the mechanism, aggregation of melanophores has been suggested as an important factor for pattern formation...

Barfin flounder larvae exhibit unique black coloration, as well as left-right asymmetry in juvenile stage as in other flatfish. In this study, we first assessed the changes in melanophores with development and then investigated their responsiveness to melanin-concentrating hormone (MCH) during metamorphosis. Larval-type melanophores appeared on both sides of the body before metamorphosis, where...

It is still unknown why dermal melanophores disappear during larval development, and why no or very few epidermal melanophores appear during and after metamorphosis, in Xenopus laevis showing periodic albinism (ap). To elucidate these points, we investigated the occurrence of depigmentation in mutant (ap/ap) melanophores during in vitro proliferation and the incidence of melanophore differentia...

The cellular bases for evolutionary changes in adult form remain largely unknown. Pigment patterns of Danio fishes are a convenient system for studying these issues because of their diversity and accessibility and because one species, the zebrafish D. rerio, is a model organism for biomedical research. Previous studies have shown that in zebrafish, stripes form by migration and differentiation ...

Adrenergic and cholinergic receptors have been studied in isolated skin melanophores of a catfish Clarias batrachus. Catecholamines induced a strong aggregatory effect on the melanophores. Melanosome aggregation induced by adrenaline and noradrenaline was partially blocked by alpha adrenergic receptor blockers and a beta receptor blocker. Cholinomimetic drugs aroused a significant dispersion of...

The skin pigment pattern of zebrafish is a good model system in which to study the mechanism of biological pattern formation. Although it is known that interactions between melanophores and xanthophores play a key role in the formation of adult pigment stripes, molecular mechanisms for these interactions remain largely unknown. Here, we show that Delta/Notch signaling contributes to these inter...