Photic sensitivity of the rhinophore in Aplysia

1979 ◽  
Vol 57 (3) ◽  
pp. 698-701 ◽  
Author(s):  
Ronald Chase
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Peripheral Nerve ◽  
Aplysia Californica ◽  
Optic Nerves ◽  
Peripheral Location ◽  
The Central Nervous System

A response to the onset of light was recorded electrophysiologically from the rhinophore nerve of Aplysia californica. Except for the optic nerves, no other peripheral nerve is known to carry photic information to the central nervous system. The result suggests a peripheral location for the extraocular photoreceptors which are known to be capable of controlling the circadian rhythm of locomotor activity.

Dissociation of circadian rhythms in rats with a hypothalamic island

1984 ◽  
Vol 246 (6) ◽  
pp. R949-R954
Author(s):  
S. Honma ◽  
K. Honma ◽  
T. Hiroshige
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Corticosterone Level ◽  
Direct Consequence ◽  
Plasma Corticosterone ◽  
Spontaneous Locomotor Activity ◽  
Medial Basal Hypothalamus ◽  
The Central Nervous System

Complete isolation of the medial basal hypothalamus, including the suprachiasmatic nuclei in the isolated island, from the rest of the central nervous system was performed in rats. The circadian rhythm of plasma corticosterone level remained essentially intact in 5 of 16 rats with complete islands, whereas that of spontaneous locomotor activity was decomposed into ultradian bursts in 15 rats, resulting in a clear dissociation of the two rhythms in four rats. One rat, whose circadian rhythm of both variables persisted after the hypothalamic isolation, showed a diurnal activity. The 24-h patterns of plasma corticosterone of the other rats could be characterized as either episodic or continuously low throughout the day. A prefeeding corticosterone peak was detected under restricted feeding in rats with episodic fluctuations but not in those with continuously low hormone levels. It is concluded that the hypothalamic island includes the fundamental structures necessary for the manifestation of the entrained circadian rhythm of plasma corticosterone in rats under ad libitum feeding, whereas it contains only a part of that for spontaneous locomotor activity. The coupling pathways from the circadian oscillator(s) to these overt rhythms seem to be separate in the central nervous system, and the circadian rhythm of plasma corticosterone is not a direct consequence of that of locomotor activity.

Functional Evidence for Neurone Fields Representing the Individual Arms Within the Central Nervous System of Octopus

1959 ◽  
Vol 36 (3) ◽  
pp. 501-511
Author(s):  
M. J. WELLS
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Test Object ◽  
The Other ◽  
Optic Nerves ◽  
The Central Nervous System ◽  
The Individual ◽  
Tactile System

1. Octopuses blinded by section of the optic nerves were trained by means of 5-10 V. a.c. shocks to reject objects that they would otherwise take. 2. With trials at 3, 5, or 20 min. intervals, in which the test object was always presented to the same arm, animals learned within four or five trials, thereafter rejecting the test object whenever it was presented. 3. When, after a succession of such negative responses, the object was presented to another arm on the other side of the octopus, the result depended upon the rate of training before the change. Thus the object was taken in the trial immediately following the arm change in nineteen out of twenty-six sets of tests with trials at 3 or 5 min. intervals, but in only two out of twelve sets with trials at 20 min. intervals; further experiments in which changes were made between arms on the same side produced similar results. 4. These results are interpreted as showing that changes occurring as a result of experience directly affecting one arm take a period of several hours to spread and become effective in determining the reactions of the rest. This in turn implies the existence of functionally independent neurone fields representing the individual arms, and is discussed in relation to what is already known about the organization of the tactile system of the octopus.

scholarly journals Metabolism of acetylcholine in the nervous system of Aplysia californica. I. Source of choline and its uptake by intact nervous tissue.

1975 ◽  
Vol 65 (3) ◽  
pp. 255-273 ◽  
Author(s):  
J H Schwartz ◽  
M L Eisenstadt ◽  
H Cedar
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nervous Tissue ◽  
Aplysia Californica ◽  
The Other ◽  
Michaelis Constant ◽  
High Affinity ◽  
The Central Nervous System

Although acetylcholine is a major neurotransmitter in Aplysia, labeling studies with methionine and serine showed that little choline was synthesized by nervous tissue and indicated that the choline required for the synthesis of acetylcholine must be derived exogenously. Aanglia in the central nervous system (abdominal, cerebral, and pleuropedals) all took up about 0.5 nmol of choline per hour at 9 muM, the concentration of choline we found in hemolymph. This rate was more than two orders of magnitude greater than that of synthesis from the labeled precursors. Ganglia accumulated choline by a process which has two kinetic components, one with a Michaelis constant between 2-8 muM. The other component was not saturated at 420 muM. Presumably the process with the high affinity functions to supply choline for synthesis of transmitter, since the efficiency of conversion to acetylcholine was maximal in the range of external concentrations found in hemolymph.

Urotensin I-like immunoreactivity in the central nervous system of Aplysia californica

Peptides ◽  
1991 ◽  
Vol 12 (4) ◽  
pp. 787-793 ◽  
Author(s):  
G.C. Gonzalez ◽  
M. Martinez-Padron ◽  
D. Ko ◽  
K. Lukowiak ◽  
K. Lederis
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Aplysia Californica ◽  
The Central Nervous System
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