Physiological evidence for peripheral ganglionic synapses in adrenergic pathways to the swimbladder of the Atlantic cod, Gadus morhua.

Effects of sympathetic and vagosympathetic nerve stimulation on the swimbladder of the cod (Gadus morhua) were studied in situ. Adrenergic nerves mediated vasoconstriction in the saline-perfused gas gland and opening of the oval. Chlorisondamine was used to locate ganglionic synapses in the adrenergic pathways. Ganglionic relays in most sympathetic vasoconstrictor pathways lay in the coeliac ganglion. A few sympathetic and all vagosympathetic vasoconstrictor pathways had peripheral relays, probably in the swimbladder nerve ganglion. Vagosympathetic pathways causing oval opening had central relays, probably in the sympathetic chain.