The Location of Penetration Barriers in the Ganglia of the American Cockroach, Periplaneta Americana (L.)

1968 ◽  
Vol 48 (2) ◽  
pp. 325-338
Author(s):  
M. E. ELDEFRAWI ◽  
A. TOPPOZADA ◽  
M. M. SALPETER ◽  
R. D. O'BRIEN
Keyword(s):  
Methylene Blue ◽  
Nervous System ◽  
Nerve Cord ◽  
Periplaneta Americana ◽  
Slow Component ◽  
Fast Component ◽  
American Cockroach ◽  
Fat Tissue ◽  
Special Protection ◽  
Nerve Cords

1. The nature and location of the barrier system which partially protects the nervous system in insects has been investigated in the American cockroach by studying the fluxes of 14C-butanol, 14C-butyrate, 14C-butylamine and 3H-butyltrimethylammonium. 2. Disruption of the sheath covering the ganglia has little effect on the influx of butanol and butyrate, but increased that of butylamine and butyltrimethylammonium. 3. 2,4-Dinitrophenol slowed the influx of only those compounds whose metabolism it blocks. 4. Effluxes show a fast and a slow component. Disruption of the sheath increases the amount but not the rate of the fast component; it raises the rate of the slow component for butanol, butyrate and butyltrimethylammonium, but not always. 5. Nerve cords stained with methylene blue and freeze-sectioned show dye concentrated in the fat tissue surrounding the nerve cord, then in the neural lamella; a little penetrated the cell bodies of glia and neurones, but the neuropile was unstained. 6. These findings suggest that the external sheath plays some part in restricting cation influx; apart from this the barrier system is a function of the whole ganglion, except that the neuropile may enjoy special protection.

scholarly journals Histological and electrophysiological Studies On The Giant Axons Of The Cockroach Periplaneta Americana

1969 ◽  
Vol 50 (3) ◽  
pp. 629-634
Author(s):  
M. E. SPIRA ◽  
I. PARNAS ◽  
F. BERGMANN
Keyword(s):  
Nerve Cord ◽  
Periplaneta Americana ◽  
American Cockroach ◽  
Giant Axons ◽  
Electrophysiological Studies ◽  
Nerve Cords

1. Nerve cords of the American cockroach were cut between the 5th and 6th abdominal ganglia. 2. All giant axons degenerated in the abdominal regions and were present but collapsed in the thoracic connectives. 3. Unilateral lesions permitted identification of ventral giant axons all along the nerve cord.

Sodium and Potassium Fluxes in the Abdominal Nerve Cord of the Cockroach, Periplaneta Americana L

1961 ◽  
Vol 38 (2) ◽  
pp. 315-322
Author(s):  
J. E. TREHERNE
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Periplaneta Americana ◽  
Unit Area ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Sodium And Potassium

1. The influx of sodium and potassium ions into the central nervous system of Periplaneta americana has been studied by measuring the increase in radioactivity within the abdominal nerve cord following the injection of 24NA and 42K. into the haemolymph. 2. The calculated influx of sodium ions was approximately 320 mM./l. of nerve cord water/hr. and of potassium ions was 312 mM./l. of nerve cord water/hr. These values are very approximately equivalent to an influx per unit area of nerve cord surface of 13.9 x 10-2 M cm. -2 sec.-1 for sodium and 13.5 x 10-12 M cm. -2 sec.-1 for potassium ions. 3. The relatively rapid influxes of these ions are discussed in relation to the postulated function of the nerve sheath as a diffusion barrier. It is suggested that a dynamic steady state rather than a static impermeability must exist across the sheath surrounding the central nervous system in this insect.

Organization of the Giant Axons of the Cockroach Periplaneta Americana

1969 ◽  
Vol 50 (3) ◽  
pp. 615-627
Author(s):  
M. E. SPIRA ◽  
I. PARNAS ◽  
F. BERGMANN
Keyword(s):  
Nerve Cord ◽  
Periplaneta Americana ◽  
Thoracic Ganglion ◽  
American Cockroach ◽  
Abdominal Ganglion ◽  
Common Pathway ◽  
Average Delay ◽  
Giant Axons ◽  
Stimulation Of

1. Stimulation of the connectives between the suboesophageal and prothoracic ganglia of the American cockroach induced ipsilateral descending spikes in the abdominal giant axons with an average delay of 0·6 msec, per thoracic ganglion. 2. Nicotine at 5 µg./ml. had no effect on conduction in the abdomen but blocked ascending responses sequentially at the 6th abdominal ganglion then at the levels of T1; T2, and T3. 3. Simultaneous descending and ascending impulses resulted in mutual extinction along the nerve cord with the point of collision depending on the interval between stimuli. 4. It is suggested that a common pathway subserves ascending and descending giant impulses and models for bi-directional conduction are discussed.

ACETYLCHOLINE IN PERIPLANETA AMERICANA L.: III. ACETYLCHOLINE IN ROACHES TREATED WITH TETRAETHYL PYROPHOSPHATE AND 2,2-BIS(p-CHLOROPHENYL)-1,1,1-TRICHLOROETHANE

1959 ◽  
Vol 37 (1) ◽  
pp. 259-272 ◽  
Author(s):  
E. H. Colhoun
Keyword(s):  
Electrical Activity ◽  
Topical Treatment ◽  
Mode Of Action ◽  
Nerve Cord ◽  
Nervous Tissue ◽  
Periplaneta Americana ◽  
Nervous Activity ◽  
Thoracic Nerve ◽  
Physiological Properties ◽  
Nerve Cords

The levels of acetylcholine (ACh) in the thoracic nerve cords of cockroaches were increased by the topical application of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and of tetraethyl pyrophosphate (TEPP), but only TEPP inhibited cholinesterase (ChE). Improvements in the correlation of symptoms, nervous activity, and ACh levels with ChE were obtained when nerve cords were homogenized in saline containing ACh, which prevented further inhibition of ChE by TEPP found to be present in blood and nervous tissue. There was a similarity in the distribution of ACh in thoracic nerve cords of roaches after topical treatment with TEPP and DDT but the physiological properties of the blood revealed differences in the mode of action of the two insecticides. The effects of blood from the poisoned insects on the electrical activity of the isolated nerve cord of roaches are discussed in relation to the penetration of the nerve cord by known neurohumors.

The Metabolism of Acetylcholine in the Intact Central Nervous System of An Insect (Periplaneta Americana L.)

1965 ◽  
Vol 43 (3) ◽  
pp. 441-454
Author(s):  
J. E. TREHERNE ◽  
D. S. SMITH
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Cholinergic System ◽  
Periplaneta Americana ◽  
Extracellular Fluid ◽  
Fibrous Layer ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Hydrolysis Of

1. A very rapid metabolism of 3H-labelled acetylcholine has been demonstrated in the intact abdominal nerve cord. It has been shown that the cholinesterase system is effective in drastically reducing the concentration of acetylcholine in the extracellular fluid of the terminal abdominal ganglion with bathing solutions of up to IO-2M acetylcholine. 2. Evidence has been obtained which indicates that an appreciable hydrolysis of acetylcholine occurs at the periphery of the nerve cord. This effect is correlated with the electronmicroscopic demonstration of regions of eserine-sensitive cholinesterase located on glial membranes in the periphery of ganglia and connectives. It is suggested that some hydrolysis of extraneous acetylcholine may occur in the fibrous layer of the nerve sheath as a result of an accumulation of diffusible acetylcholinesterase in this region. 3. The results are discussed in relation to the possible involvement of the conventional cholinergic system in synaptic transmission in the central nervous system of this insect.

Studies of Cardio-Regulation in the Cockroach, Periplaneta Americana

1971 ◽  
Vol 54 (2) ◽  
pp. 329-350
Author(s):  
T. MILLER ◽  
P. N. R. USHERWOOD
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Heart Muscle ◽  
Periplaneta Americana ◽  
Ganglion Cells ◽  
Muscle Fibres ◽  
Cardiac Ganglion ◽  
Cardiac Nerve ◽  
The Central Nervous System ◽  
Nerve Cords

1. The heart of Periplaneta americana is segmentally innervated from the central nervous system by three types of neurone. Two of these types of neurones are neurosecretory; one type contains large granules, the other small granules. The segmental nerves are paired structures which join paired lateral cardiac nerve cords. Both types of neurosecretory neurone liberate their contents in the lateral cardiac nerve cords. The neurones with the small granules also synapse with the myocardium as well as with intrinsic cardiac neurones in the lateral cardiac nerve cords. The third type of neurone from the central nervous system is an ordinary efferent neurone and it synapses with the cardiac ganglion cells. 2. A heart chamber is associated with about six cardiac ganglion cells, three on either side. These send processes up and down the lateral cardiac nerve cord and make synaptic contact with the myocardium. 3. The myocardium is multiterminally and polyneuronally innervated, and electrical coupling between muscle fibres appears to be the rule. The fibres are spontaneously active and generate spike-like electrically excited responses. The timing of the electrically excited responses is influenced by the input from the cardiac ganglion cells which evoke a burst of synaptic potentials during diastole. 4. Control of the cockroach heart appears to be organized on three levels. The basic rhythm is myogenic. The timing of the contractions is influenced by inputs from the intrinsic cardiac ganglion cells possibly via a feedback mechanism involving the contractions of the heart muscle. Finally, the activities of the heart muscle and the cardiac ganglion cells are influenced by inputs from the central nervous system.

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