. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 414 CHRISTIAN WEBER ocellar cavity pigmented cup optic ganglion optic nerve. mm UUWIAJ mm 20 p m 20 pm 40 pm 40 pm FIGURE 1. Summary diagram of receptor cell arrangement in the ocellus of Sarsia tubulosa. AX, axon; MR, microvilli region; PC, pigment cell; RC, receptor cell; RP, receptor cell process. 1979) of the two lines of evolution of photoreceptors, the photoreceptor cells of Cnidaria belong to the same evolutionary line as those of vertebrates. While the rhabdomeric photoreceptors respond with a depolarization, cilia-d
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 414 CHRISTIAN WEBER ocellar cavity pigmented cup optic ganglion optic nerve. mm UUWIAJ mm 20 p m 20 pm 40 pm 40 pm FIGURE 1. Summary diagram of receptor cell arrangement in the ocellus of Sarsia tubulosa. AX, axon; MR, microvilli region; PC, pigment cell; RC, receptor cell; RP, receptor cell process. 1979) of the two lines of evolution of photoreceptors, the photoreceptor cells of Cnidaria belong to the same evolutionary line as those of vertebrates. While the rhabdomeric photoreceptors respond with a depolarization, cilia-derived photore- ceptors are hyperpolarizing in general. The question then arises whether the phys- iology of Sarsia's receptors is also like that of vertebrate receptors? In this paper I describe the electroretinogram of a jellyfish, Sarsia tubulosa (Hydromedusae), and map the different patterns of photo-induced responses at the optic ganglion which surrounds the receptive field of the ocellus. MATERIALS AND METHODS Specimens of Sarsia tubulosa (M. Sars) were collected from the water around Victoria, B. C., Canada and from the dock at the Friday Harbor Laboratories of the University of Washington. They were either maintained in cool, running sea water and exposed to daylight or transferred to a holding tank in a dark room at 8°C. The water in the tank was continuously replenished with fresh, filtered seawater. For electrical recording, whole or partially dissected animals were pinned down on a silicone elastomer plastic (#184; Sylgard, Dow Corning Corp.) layer in the recording dish. Experiments were done in seawater at 8 to 10°C. Recordings were made from ocelli which had been dark-adapted for at least 15 min. (This time for full dark adaptation was determined experimentally). The extracellular recordings were made with plastic suction electrodes with external tip diameters ranging from 20 to 25 ( and with glass microelectrodes (Ultra Tip, Federick Haer & Co., #30- 30-
Size: 2496px × 1001px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
