Neurosecretion and Retinal Pigment Movement in Crustaceans

Abstract

Retinal and integumentary pigment cells are two types of crustacean effectors known to be hormonally influenced by a neurosecretory product from the eyestalks. Initial studies by Hanström (1937) and subsequently by Brown (1940) indicated that the Sinus gland is probably the major source of chromatophore-activating substances in the crustacean eyestalk, but later investigators [Bliss, Durand and Welsh (1954), Knowles (1953), Potter (1954) ] showed histologically that a complex neurosecretory network exists in the crustacean central nervous system and that major pathways of this network from the ventral nerve cord and optic ganglia terminate in the sinus gland. The sinus gland thus appears to consist largely of the secretion-laden endings of neurones whose cell bodies might be located at some distance from the sinus gland itself. A series of tests by injection experiments supplied additional evidence that chromatophore-activating substances were present in the combined or separated optic ganglia of the eyestalk and in the ventral nerve cord as well as in the sinus gland [Bowman (1949), Brown (1950), Sandeen (1950)].