A novel approach to AVT and IT studies in fish brain and pituitary: in vitro perfusion technique.

The study was designed to develop a new procedure for perfusion of brain and pituitary explants collected from three-spined stickleback (Gasterosteus aculeatus) and round goby (Neogobius melanostomus). The procedure was elaborated for studies of arginine vasotocin (AVT) and isotocin (IT) release from explants of both species. AVT and IT, analogs of mammalian vasopressin and oxytocin, are neurohormones produced in hypothalamus and released in neurohypophysis of Teleostei. Both nonapeptides are used as biomarkers of fish well being. Three perfusion sets were applied to test the method of medium transport into gradient container, without or with aeration. Medium supply to the gradient container from the top, without aeration is recommended only for short-term studies. Aeration of the medium with a mixture of 95% O(2) and 5% CO(2) at a pressure of 127.51 mm Hg is necessary for a long-term research. Transport of one or two media in the gradient container from the top and the bottom, simultaneously, requires aeration with a mixture of 95% O(2) and 5% CO(2) at a pressure of 315.03 mm Hg. Although the presented procedure has been elaborated for studies of AVT and IT in fish explants, after only minor modification, if any, it can serve many other purposes.