The distribution of histamine-immunoreactive neurons in the ventral nerve cord of the cricket, Gryllus bimaculatus

1996 ◽  
Vol 286 (3) ◽  
pp. 393-405 ◽  
Author(s):  
Michael Hörner ◽  
Johannes Helle ◽  
Friedrich-Wilhelm Schürmann
1995 ◽  
Vol 280 (3) ◽  
pp. 583-604 ◽  
Author(s):  
Michael H�rner ◽  
Ulrike Sp�rhase-Eichmann ◽  
Johannes Helle ◽  
Br�ne Venus ◽  
Friedrich-Wilhelm Sch�rmann

2001 ◽  
Vol 204 (13) ◽  
pp. 2265-2275 ◽  
Author(s):  
Michael Gebhardt ◽  
Hans-Willi Honegger

SUMMARY We investigated five different descending brain interneurons with dendritic arborizations in the deutocerebrum in the crickets Gryllus bimaculatus and G. campestris. These interneurones convey specific antennal mechanosensory information to the ventral nerve cord and all responded to forced antennal movements. These interneurones coded for velocity and showed preferences for distinct sectors of the total range of antennal movements. Their axons descended into the posterior connective either ipsilateral or contalateral to the cell body. Electrical stimulation of sensory nerves indicated that the interneurons received input from different afferents of the two antennal base segments. One interneuron had a particularly large axon with a conduction velocity of 4.4ms−1. This was the only one of the five interneurons that also received visual input. Its activity was reduced during voluntary antennal movements. The reduction in activity occurred even after de-efferentation of the antenna, indicating that it had a central origin. Although we do not have experimental evidence for behavioural roles for the descending antennal mechanosensory interneurons, the properties described here suggest an involvement in the perception of objects in the path of the cricket.


1995 ◽  
Vol 280 (3) ◽  
pp. 583-604 ◽  
Author(s):  
Michael H�rner ◽  
Ulrike Sp�rhase-Eichmann ◽  
Johannes Helle ◽  
Br�ne Venus ◽  
Friedrich-Wilhelm Sch�rmann

Author(s):  
Roy J. Baerwald ◽  
Lura C. Williamson

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.


Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1611-1622 ◽  
Author(s):  
Go Shioi ◽  
Michinari Shoji ◽  
Masashi Nakamura ◽  
Takeshi Ishihara ◽  
Isao Katsura ◽  
...  

Abstract Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.


2001 ◽  
Vol 41 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Yoshiichiro Kitamura ◽  
Yuichi Naganoma ◽  
Haruhito Horita ◽  
Hiroto Ogawa ◽  
Kotaro Oka

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