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July 1933

Humoral Agents in Nervous Activity, with Special Reference to Chromatophores.

Arch NeurPsych. 1933;30(1):243. doi:10.1001/archneurpsyc.1933.02240130251025

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Thirty years ago Bayliss and Starling discovered secretin, the first hormone to be described. This introduced the conception of humoral as contrasted with nervous control. In this book, Professor Parker utilizes many salient facts about the behavior of chromatophores in cold-blooded vertebrates and the Crustacea of the invertebrates from the contrasted points of view of nervous and humoral control. When denervated, fish chromatophores still react to epinephrine. Amphibian melanophores are controlled by varying amounts of pituitary intermedia secretion rather than by nerves. These are examples of humoral control of this type of effector, in the apparent absence of nerves. The author then advances the idea that when nerves are present they may secrete something which is the real activating agent. This would be formed at synapses and other nerve terminals. In the giant fibers of the earthworm there are macrosynapses, which consist of an oblique apposition of the terminals of

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