... at rhabdoms have been described in detail in white-eyed Drosophila maintained under artificial light. Here we tested whether protein levels at rhabdoms change significantly in the highly pigmented lateral eyes of wild-caught Limulus polyphemus maintained in natural diurnal illumination and whether...

... in the literature of photoreceptors from vertebrates and invertebrates that break this rule is increasing. Here, we describe a newly discovered Limulus opsin, Limulus opsin5, which is significantly different from previously characterized Limulus opsins, opsins1 and 2. We show that opsin5 is co-expressed...

...Jack A. Benson ABSTRACT The isolated, intact heart of the marine arachnid Limulus polyphemus continues to beat in vitro for many hours. Application of γ- aminobutyric acid (GABA) decreased the heart beat frequency with a threshold of 3×10 −7 moll −1 and an EC 50 of 2·0±0·6×10 −5 moll −1 (mean±S.D...

...J. R. Groome; W. H. Watson, III ABSTRACT The biochemical mechanisms by which octopamine, catecholamines and the peptide proctolin exert their actions on Limulus cardiac muscle were investigated. Amines produced long-lasting increases in the amplitude of contractions evoked by electrical stimulation...

...George J. Augustine; Raymond H. Fetterer ABSTRACT Octopamine (OCT), dopamine (DA), epinephrine (EPI) and norepine-phrine (NE) are endogenous excitors of the Limulus heart. The cellular sites of action of these amines were investigated by recording responses of neurones in the cardiac ganglion...

...Winsor H. Watson, III; Toshinori Hoshi; John Colburne; George J. Augustine ABSTRACT The responses of Limulus cardiac neuromuscular junctions and cardiac muscle cells to four endogenous amines were determined in order to identify the cellular targets underlying amine modulation of heartbeat...

...W. H. Watson, III; G. J. Augustine; J. A. Benson; R. E. Sullivan ABSTRACT Synthetic proctolin increases the force but not the rate of heart contractions of Limulus in a time- and dose-dependent manner. The threshold of this effect is 3 X 10 −10 M and the ED S0 is approximately 10 −10 M...