Sue W. Fingerman

Effects of exogenous ecdysones on the molt cycles of fourth and fifth stage american lobsters, Homarus americanus

Abstract 1. 1. Bilateral ablation of the eystalks of the lobster, Homarus americanus, results in the acceleration of proecdysial preparations and precocious initiation of ecdysis. 2. 2. Injection of either α-ecdysone or 20-hydroxyecdysone into fourth stage lobsters in stage D0 of the molt cycle accelerated proecdysial preparations and led to precocious initiation of ecdysis. 3. 3. Lobsters which initiated precocious ecdysis in response to 20-hydroxyecdysone died during the initial stage of ecdysis (E1) whereas the α-ecdysone-injected lobsters either completed ecdysis successfully or died in the later stages of ecdysis (E2 or E3). 4. 4. α-Ecdysone was ineffective in inducing proecdysis and shortening the molt cycle in fifth stage lobsters when injected during early postecdysial stages but was effective when injected late in the intermolt stage and in early proecdysis (D0).

Circadian rhythms of brain 5-hydroxytryptamine and swimming activity in the teleost, Fundulus grandis

Abstract 1. The 5-hydroxytryptamine (5-HT, serotonin) concentration in the brain of male specimens of the teleost, Fundulus grandis , was determined for 24-hr periods. 2. The mean 5-HT concentrations in whole brains was higher betweeen 8:30 a.m. and 4:30 p.m. than between 8:30 p.m. and 4:30 a.m. 3. Male Fundulus grandis exhibited a diurnal swimming activity pattern; maximum activity occurred at 12:30 p.m. and minimum activity was at 12:30 a.m. 4. Males injected with 5-HT were less active than the saline-injected controls. 5. Male fishes kept in constant darkness for one week had significantly less brain 5-HT than males kept in constant light. 6. It is suggested that 5-HT has a normal role in regulating the swimming activity of this fish.

Antagonistic actions of dopamine and 5-hydroxytryptamine on color changes in the fiddler crab, Uca pugilator.

Abstract 1. 1. Dopamine (DA) produces pigment concentration in the erythrophores of intact fiddler crabs, but has no effect on the erythrophores in isolated legs. 2. 2. DA antagonizes the red pigment-dispersing action of 5-hydroxytryptamine. 3. 3. It is hypothesized that DA triggers release of red pigment-concentrating hormone.

EFFECTS OF NOREPINEPHRINE AND NOREPINEPHRINE AGONISTS AND ANTAGONISTS ON THE MELANOPHORES OF THE FIDDLER CRAB UCA PUGILATOR

Norepinephrine produces dose-related pigment dispersion in the melanophores of intact and eyestalkless fiddler crabs, Uca pugilator, but has no effect on the melanophores in isolated legs. 2. The effects of agonists and antagonists of norepinephrine on the rates of melanin dis- persion and concentration were determined. 3. The results are consistent with the hypothesis that norepinephrine exerted its effect by acting on the central nervous system to trigger the release of melanin-dispersing hormone. Migration of the pigment in the chromatophores of the fiddler crab Uca pugi- lator is hormonally regulated (Carlson, 1935; Sandeen, 1950; Brown, 1950; Fin- german, 1956a). A series of experiments performed with this crab has revealed that release of red pigment-dispersing hormone is triggered by 5-hydroxytrypt- amine (=serotonin) (Rao and Fingerman, 1970b) whereas release of red pigment- concentrating hormone is triggered by dopamine (Fingerman and Fingerman, 1977). However, no one has as yet identified a neurotransmitter substance which appears to be involved in triggering release of melanin-dispersing hormone (MDH), melanin-concentrating hormone (MCH), white pigment-dispersing hor- mone, or white pigment-concentrating hormone in any species of fiddler crab. Abramowitz and Abramowitz (1938) tested both acetylcholine and epinephrine on melanophores of Uca pugilator, and reported that they had no effect in either producing dispersion or aggregation of the pigment in these cells. Although Bau- chau and Mengeot (1966) found that 5-hydroxytryptamine will produce dispersion of the pigment in the melanophores of the shore crab Carcinus maenas, Rao and Fingerman (1970a) observed that this compound has no such effect on the me- lanophores of Uca pugilator. Presented below are the results of a series of ex- periments which led to identification of norepinephrine as a neurotransmitter substance that appears to be involved in triggering release of MDH in Uca pu- gilator. Experiments were also performed to identify a neurotransmitter sub- stance that might be involved in release of white pigment-dispersing hormone, but these were unsuccessful.

Circadian variation in the levels of red pigment-dispersing hormone and 5-hydroxytryptamine in the eyestalks of the fiddler crab, Uca pugilator☆

1. Circadian variations in the levels of red pigment-dispersing hormone (RPDH) and 5-hydroxytryptamine (5-HT) in the eyestalks of the fiddler crab, Uca pugilator, were found. 2. 5-HT in whole eyestalks peaked at midnight and was at a minimum at 1800 hr. 3. RPDH both in whole eyestalks and in sinus glands alone taken the eyestalks attained maximum level at 0600 hr and was at a minimum at 1800 hr. The minimum RPDH level in the optic ganglion alone from the eyestalks was also at 1800 hr but the peak RPDH level in the optic ganglia occured at midnight. 4. The possible role of 5-HT in controlling release of RPDH is discussed.

Effects of a polychlorinated biphenyl and a polychlorinated dibenzofuran on molting of the fiddler crab,Uca pugilator

Several species of aquatic crustaceans have been found to accumulate polychlorinated biphenyls (PCBs) from their environment. Specifically~ NIMMO et al. (1971b) showed that the fiddler crab, Uca pugi!ator , accumulates the PCB, Aroclor 1254~ from contaminated sediments. However, there are no published reports on the possible effects of PCBs on the physiology of the fiddler crab. We undertook a series of experiments to determine the effect of the PCB, Aroclor 1242, on the rate of molting of the fiddler crab, Uc__~apugilator. Fairly recently, however, polychlorinated dibenzofurans (PCDFs) have not only been shown to be impurities in PCBs, but also to exceed the toxicity of PCBs in chick embryo assays by approximately four to six orders of magnitude (VOS et al., 1970; BOWES et al., 1975a,b). Consequently, reported effects of PCBs, as in mortality studies such as that of NIMMO et al. (1971a) with the pink shrimp, Penaeus duorarum, may have been due in large measure to contaminating PCDFs. Therefor~ in the present investigation experiments were also performed to determine the effect of a PCDF on the rate of molting, the PCDF concentration used being that found in Aroclors by BOWES et al. (1975b). Use of such a PCDF concentration would allow us to determine whether any effects on molting were due to Aroclor 1242 or to perhaps only PCDF contamination of the Aroclor.

Separation, Assay, and Properties of the Distal Retinal Pigment Light-Adapting and Dark-Adapting Hormones in the Eyestalks of the Prawn Palaemonetes vulgaris

Migration of the distal retinal pigment in the compound eye of the prawn Palaemonetes vulgaris is regulated by antagonistic light-adapting (Kleinholz 1936) and dark-adapting hormones (Brown, Hines, and Fingerman 1952; Fingerman, Lowe, and Sundararaj 1959; Fingerman and Mobberly 1960). Properties of the lightadapting hormone such as stability, solubility, and dialyzability are better known than those of the dark-adapting hormone. Both hormones appear to be polypeptides (Fingerman and Mobberly 1960; Kleinholz et al. 1962). The extent of the light-adapting response evoked by extracts of the supra-

The effects of biogenic amines on color changes of the fiddler crab, Uca pugilator: Further evidence for roles of 5-hydroxytryptamine and dopamine as neurotransmitters triggering release of erythrophorotropic hormones☆

Abstract 1. 1. The effects of 5-hydroxytrytryptaminergic potentiators (Fluvoxamine and Fluoxetine), a 5-hydroxytryptaminergic antagonist (LY53857), a dopaminergic agonist (ADTN) and dopaminergic antagonists (Spiroperidol and γ-hydroxybutyrate) on color changes involving the erythrophores of the fiddler crab, Uca pugilator, were determined. 2. 2. The results were consistent with the hypotheses that 5-hydroxytryptamine triggers release of a red pigment-dispersing hormone and that dopamine triggers release of a red pigment-concentrating hormone in Uca pugilator.

The effects of 5-hydroxytryptamine depletors and monoamine oxidase inhibitors on color changes of the fiddler crab, Uca Pugilator: Further evidence in support of the hypothesis that 5-hydroxytryptamine controls the release of red pigment-dispersing hormone

Abstract 1. The monoamine oxidase (MAO) inhibitors, iproniazid and nialamide, produced acceleration of the red pigment dispersion which occurs after intact crabs are transferred from a white to a black background but caused a decrease in the rate of red pigment concentration which occurs following transfer of intact crabs from a black to a white background. 2. In contrast, the 5-HT depletors, p -chlorophenylalanine and reserpine, produced effects opposite to those observed with the MAO inhibitors on the rates of migration of the red chromatophoric pigment in response to background changes. 3. These drugs do not have a direct effect on the red chromatophores. The drugs used did not produce either concentration or dispersion of the pigment in the red chromatophores of isolated legs. 4. The results obtained with these drugs which are known to alter the level of 5-HT in nerve tissue are consistent with the hypothesis that 5-HT controls the release of red pigment-dispersing hormone.

Evidence for a substance in the eyestalks of brachyurans that darkens the shrimpCrangon septemspinosa

1. Fractions, obtained by gel chromatography, of eyestalk extracts from the fiddler crabUca pugilator, the shore crabCarcinus maenas and the shrimpCrangon septemspinosa darkenedUca andCrangon by evoking black pigment dispersion. 2. In addition to the fractions with black pigment-dispersing activity, other fractions possessing black pigment-concentrating activity inUca andCrangon were obtained from eyestalk fromUca andCrangon. The frations of eyestalk extracts fromCarcinus were not assayed for a black pigment-concentrating substance.