Work

Development of an In Vitro Bioassay System to Examine the Effects of Bioactive Substances on the Chromatophores’ Movement Using the Epidermis of the Bigfin Reef Squid Sepioteuthis lessoniana

Year: 2023

Type: article

Abstract: To examine the neurophysiological regulation of squid chromatophores, an in vitro bioassay system was developed using the epidermis of the bigfin reef squid Sepioteuthis lessoniana.The squid epidermis was sectioned under anesthesia with 0.1% ethanol and stretched over a kimwipe soaked with artificial seawater.In cephalopods, chromatophores have three types of pigments: orange, yellow, and dark brown; however, only chromatophores with dark brown pigment were analyzed in this study.After stabilizing the contraction-relaxation movement of the chromatophore, the following bioactive substances were added to the separated epidermis: acetylcholine, melanocyte-stimulating hormone, and noradrenaline (each 1 mM); and the chromatophores' movement was observed under a microscope while taking videos.The video-based analysis of squid chromatophores indicated that acetylcholine and -melanocyte-stimulating hormone had no effect on the squid chromatophores movement under present conditions.Conversely, noradrenaline (1 mM) promoted contraction-relaxation squid chromatophores' movement.The accelerated movement of chromatophores was inhibited by the addition of yohimbine (1 mM) but not by propranolol (1 mM).To the best of our knowledge this is the first report determining that noradrenaline promotes contraction-relaxation movement of the chromatophore via -2 receptors in the bigfin reef squid because yohimbine is known to be an 2-adrenergic receptor blocker.In current study, squid chromatophores responded well to bioactive substances including inhibitors.Collectively, our in vitro bioassay provides an effective model to investigate the mechanism of contraction-relaxation movement of squid chromatophores.

Source: International Journal of Zoological Investigations

DOI: 10.33745/ijzi.2023.v09i01.106