Topic
Uca pugilator
About: Uca pugilator is a research topic. Over the lifetime, 376 publications have been published within this topic receiving 12303 citations.
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TL;DR: 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.
Abstract: 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.
42 citations
TL;DR: These results provide the first evidence that an opioid system is involved in the control of reproduction in a crustacean.
42 citations
TL;DR: Results strongly suggest that cadmium acts at least in part to increase the secretion of GIH from the sinus gland, which could then act by inhibiting secretion of GSH by the thoracic ganglion, directly inhibit the oocytes.
41 citations
TL;DR: Persistent rhythms of primary solar and primary lunar frequencies are described for O2-consumption of two species of fiddler crabs and for the salamander, Triturus viridescens, and these rhythms appear to be statistical rather than overt ones.
Abstract: 1. Persistent rhythms of primary solar and primary lunar frequencies are described for O2-consumption of two species of fiddler crabs, Uca pugnax and Uca pugilator, and for the salamander, Triturus viridescens.2. These rhythms appear to be statistical rather than overt ones. The forms of the rhythms become apparent only upon the averaging of several days of data.3. The form of the daily variation in O2-consumption shows a monthly variation, the form of the rhythm for a two-week period straddling a new moon being different from the form for a two-week period straddling a full moon.4. The hourly values in the rate of respiration show a significant correlation with the concurrent rate of barometric pressure change. In all three species, the rate of O2-consumption increases in a direct relationship with the concurrent rate of barometric pressure fall and decreases in a direct relationship with the rate of pressure rise.5. There appears, in some instances, to be a correlation with the absolute concurrent barom...
40 citations
TL;DR: In this paper, a detailed description of recent experiments with the chromatophores of fiddler crabs is given. And the role that post-commissural organs might have in regulating the melanin dispersion of the fiddler crab during different portions of the daily rhythm of color change is discussed.
Abstract: A general summary of the current status of the control of crustacean pigmentary effectors is followed by a detailed description of recent experiments with the chromatophores of fiddler crabs. Under appropriate experimental conditions eyestalkless fiddler crabs, Uca pugilator , can exhibit an overt daily rhythm of melanin dispersion. Otherwise, the melanin of eyestalkless crabs remains maximally concentrated. Electrophoretic analysis revealed three peaks of melanin-dispersing activity for sinus glands of Uca pugilator , two for the supraesophageal ganglia, one for the circumesophageal connectives, and one for blood. What appeared to be the same electronegative substance was found in every electrophorogram regardless of whether one, two, or three peaks were present. In addition, a melanin-concentrating substance was found after electrophoresis of circumesophageal connectives. The morphology of postcommissural organs from two species of fiddler crabs is described also. Extracts of post-commissural organs from Uca pugilator were chromatophorotropically active. The extracts were most effective in concentrating red pigment but could also disperse the red and black pigments. Post-commissural organs of crabs had not been assayed previously on any system. Finally, the role that post-commissural organs might have in regulating chromatophores of fiddler crabs during different portions of the daily rhythm of color change is discussed.
40 citations