text: Light production in Porichthys notatus has been found to be triggered through an adrenergic mechanism. The sympathetic nervous system of the fish is responsible for triggering bioluminescence in the photocytes. As a response to being triggered by an norepinepherine, epinephrine, or phenylephrine, the photocyte exhibits a quick flash and then emits light that slowly fades in intensity. Stimulation by isoproterenol was found to cause an only a slow fading illumination. The amplitude of the quick flash, referred to as the "fast response", was higher when the concentration of neurotransmitter stimulating it increased. A great dal of variation in luminescence was exhibited in the photocytes of different fish. Variation also existed depending on what time of year the photocytes were collected from the fish. Stimulation from phenylephrine was found to produce a less intense response than that of epinephrine or norepinephrine. Phentolamine was shown to inhibit the effect of stimulation by phenylephrine completely and of epinephrine and norepinephrine to a lesser degree. Clonidine was shown to have an inhibitory effect on the fast response but no effect on the slow response. The photocytes of Porichthys are known to be extensively innervated.