Ultrastructural distribution of cholinesterase activity in the ventral nerve cord of the earthworm Lumbricus terrestris

Histochemie ◽  
1969 ◽  
Vol 18 (2) ◽  
pp. 177-190 ◽  
Author(s):  
H. Teräväinen
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Cholinesterase Activity ◽  
Lumbricus Terrestris ◽  
Earthworm Lumbricus

Facilitation in the Rapid Response of the Earthworm, Lumbricus Terrestris L

1966 ◽  
Vol 45 (1) ◽  
pp. 141-150
Author(s):  
M. B. V. ROBERTS
Keyword(s):  
Nerve Cord ◽  
Lumbricus Terrestris ◽  
Rapid Response ◽  
Giant Fibre ◽  
Rapid Responses ◽  
Earthworm Lumbricus ◽  
Marked Tendency

1. Successive rapid responses of the earthworm show a marked tendency to increase in size on repetition. 2. It is shown that this "staircase" phenomenon is not due to peripheral facilitation either on the afferent or efferent side of the reflex, but to summation in the nerve cord and evidence is presented that it occurs at "giant-to-motor" junctions. 3. Facilitation is most pronounced in preparations whose "giant-to-motor" junctions are accommodated. In such cases a single impulse in the median giant fibre is ineffective, two or more being required to produce a rapid response throughout the length of the animal. 4. Fatigue and facilitation in the earthworm is discussed in relation to similar phenomena in other invertebrates.

scholarly journals On the Physiology and Pharmacology of the Earthworm Gut

1939 ◽  
Vol 16 (2) ◽  
pp. 184-197
Author(s):  
K. S. WU
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Buccal Cavity ◽  
Lumbricus Terrestris ◽  
Threshold Concentration ◽  
Nerve Ring ◽  
Wide Range ◽  
Earthworm Gut ◽  
Different Parts ◽  
Allolobophora Longa

1. The gut of Lumbricus terrestris and Allolobophora longa was studied. 2. The normal movements of the different parts of the gut, isolated and suspended in Ringer's fluid, are described. 3. Acetylcholine excites all parts of the gut. The "crop and gizzard" preparation is very sensitive to acetylcholine and shows a graded series of responses over a wide range of concentrations. It may therefore prove to be useful in the assay of acetylcholine. 4. The action of acetylcholine on the crop and gizzard is only slightly increased by eserine or prostigmine. The potentiation is especially noticeable in the presence of other drugs (adrenaline, histamine) which interfere with the acetylcholine action. 5. The action of acetylcholine on the crop and gizzard is abolished by atropine. 6. Adrenaline excites the buccal cavity, pharynx and oesophagus in all concentrations. On the crop, gizzard and intestine it has two actions, inhibition above and excitation below a certain threshold concentration, whose magnitude varies somewhat from worm to worm. 7. The action of adrenaline is slightly increased by ephedrine, and abolished by ergotoxine. 8. The actions of choline, histamine, potassium and calcium on the crop and gizzard are described. 9. The crop and gizzard receive two sets of nerves: (a) Exciting nerves, coming along the gut wall from the circumpharyngeal nerve ring; action abolished by atropine; probably cholinergic. (b) Inhibiting nerves, coming along the septa from the ventral nerve cord; action abolished by ergotoxine; probably adrenergic.

Extracellular filaments in the perineurium of the florida lobster, Panulirus argus

1987 ◽  
Vol 45 ◽  
pp. 784-785
Author(s):  
Roy J. Baerwald ◽  
Lura C. Williamson
Keyword(s):  
Blood Brain Barrier ◽  
Glial Cells ◽  
Tannic Acid ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Florida Keys ◽  
Panulirus Argus ◽  
Brain Barrier ◽  
Cacodylate Buffer ◽  
Nerve Cords

In arthropods the perineurium surrounds the neuropile, consists of modified glial cells, and is the morphological basis for the blood-brain barrier. The perineurium is surrounded by an acellular neural lamella, sometimes containing scattered collagen-like fibrils. This perineurial-neural lamellar complex is thought to occur ubiquitously throughout the arthropods. This report describes a SEM and TEM study of the sheath surrounding the ventral nerve cord of Panulirus argus.Juvenile P. argus were collected from the Florida Keys and maintained in marine aquaria. Nerve cords were fixed for TEM in Karnovsky's fixative and saturated tannic acid in 0.1 M Na-cacodylate buffer, pH = 7.4; post-fixed in 1.0% OsO4 in the same buffer; dehydrated through a graded series of ethanols; embedded in Epon-Araldite; and examined in a Philips 200 TEM. Nerve cords were fixed for SEM in a similar manner except that tannic acid was not used.

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