Atya Lanipes Research Articles

Organic calcium channel blockers generate the coexistence of two different types of action potentials in the same muscle membrane following chemical induction of excitability

1. Following exposure to the sulfhydryl reagents known as α,β-unsaturated carbonyl compounds, the ventroabdominal flexor muscles of the crustacean Atya lanipes, which are normally completely inexcitable, generate trains of overshooting calcium action potentials; the effects of organic calcium channel antagonists and potassium channel blockers on the chemically-induced trains of action potentials have been studied. 2. Verapamil and D600, at micromolar concentrations, elicit the appearance of slow, cardiac-like action potentials which coexist with the much faster chemically-induced calcium spikes, transforming the regular repetitive firing into a cyclic bursting pattern. 3. Bepridil (1 μM) decreases the frequency of firing of the action potentials, probably by increasing the threshold for the activation of a population of the chemically-induced calcium channels. 4. The potassium channel blockers, TEA (30–40 mM) and quinidine (100–200 μM), delayed the rate of repolarization of the chemically-induced action potentials; none of the potassium channel blockers, however, induced the appearance of repetitive spike activity.

Generation of calcium action potentials in crustacean muscle fibers following exposure to sulfhydryl reagents

1. The ventroabdominal flexor muscles of the crustacean Atya lanipes, which are normally completely inexcitable, generate trains of overshooting calcium action potentials after exposure to the sulfhydryl reagents known as α,β -unsaturated carbonyl compounds. 2. The chemically induced action potentials are abolished by protein reagents specific for guanidino and amino groups. 3. Attempts to induce excitability by the use of agents that block potassium conductance were without success. 4. It is proposed that calcium channels are made functional by the covalent modification of a calcium protochannel, via the interaction between the introduced carbonyl group and existing arginine residues.

The distribution of freshwater shrimps (Atyidae and Palaemonidae) in Jamaica

The distribution of freshwater shrimps in Jamaica is presented. Atya innocous, Atya lanipes, Atya scabra, Micratya poeyi and Macrobrachium heterochirus were found only in the high-gradient streams characteristic of eastern and north-eastern parishes. Macrobrachium acanthurus, Jonga serrei, and Potimirim mexicana were found only in the low-gradient streams characteristic of western and southwestern parishes. Macrobrachium faustinum, Macrobrachium carcinus, and Xiphocaris elongata were distributed throughout Jamaica. Oxygen, temperature, and current speed were the physical features of the streams most likely influencing this distribution. It was observed that species in high-gradient streams had larvae which required high salinity for development, and those in low-gradient streams had larvae with low salinity requirements. It is argued that larval salinity preferences during the marine planktonic stage of the life history could allow larvae to select an appropriate river prior to its being invaded by juveniles.

Atya Lanipes Holthuis, 1963, in Jamaica, Including Taxonomic Notes and Description of the First Larval Stage (Decapoda, Atyidae)

[Atya lanipes Holthuis, 1963, est signalee pour la premiere fois de la Jamaique. Il apparait que cette espece est exceptionnellement variable ou qu'elle couvre plus d'un taxon definissable. La couleur de l'espece est decrite pour la premiere fois, ainsi que la morphologie detaillee des larves du premier stade., Atya lanipes Holthuis, 1963, est signalee pour la premiere fois de la Jamaique. Il apparait que cette espece est exceptionnellement variable ou qu'elle couvre plus d'un taxon definissable. La couleur de l'espece est decrite pour la premiere fois, ainsi que la morphologie detaillee des larves du premier stade.]