PubMed Health⌕ Search

Biomedical subjects

V E Shashoua

Publications and source records attributed to V E Shashoua.

54 records · Page 3Linked to original sources
PubMed1978

Effect of antisera to beta and gamma goldfish brain proteins on the retention of a newly acquired behavior.

The metabolism of 3 brain cytoplasmic proteins (alpha, beta, and gamma) increases markedly when goldfish acquire a new pattern of behavior. Antisera specific to beta and beta + gamma proteins were prepared and injected into the fourth ventricle of the brains of trained animals at 8 and 24 h after the initiation of training. When tested 3 days later, such goldfish (N = 98) could not recall the training; whereas trained goldfish (N = 97) receiving non-immunized rabbit serum had complete recall of the behavior. Also no amnesia was obtained in control experiments in which trained goldfish were injected with an antiserum to a neural surface membrane protein NS-6. The fact that antisera to beta + gamma had no toxic effects was demonstrated by injecting them prior to training; no effects on the rate of acquisition and recall of the behavior was found. The antisera to beta + gamma were effective in inhibiting recall of the training when they were injected any time between 3 h up to 48 h after training; no effect was obtained at 72 h post training. These results are consistent with the hypothesis that beta and gamma might have some functional role in the plasticity of the CNS.

Animals↗
PubMed1977

Localization of a brain protein metabolically linked with behavioral plasticity in the goldfish.

Immunofluorescent methods were used to map the distribution of a soluble, 32,000 dalton brain protein, the synthesis of which increases when goldfish master a vestibulomotor task. The protein was found to be associated with a family of approximately 15,000 cells which vary in diameter from 8 to 15 micrometer and possess multiple processes. These cells are distributed near periventricular and external surfaces from the spinal cord up through the forebrain, but are most abundant in the broad ependymal zones of the optic tectum and vagal lobes. This localization pattern suggests that one of the major changes in brain protein metabolism associated with performance of the 'float-training' task in goldfish may reflect the activity of a non-neuronal population of brain cells.

Animals↗
PubMed1977

Brain protein metabolism and the acquisition of new behaviors. II. Immunological studies of the alpha, beta and gamma proteins of goldfish brain.

In a previous study, the labeling pattern of three proteins (alpha, beta and gamma) in goldfish brain was found to change after the animals successfully acquired a new pattern of behavior. In the present study, these proteins were isolated from the brain cytoplasmic fraction, purified by successive gel electrophoresis and used as antigent to immunize rabbits. Antisera containing antibodies to two of the proteins (beta and gamma) were obtained. These gave single precipitin bands when plated against the antigens and a mixture of the total cytoplasmic proteins. The distribution of beta and gamma in brain subcellular fractions and in a variety of goldfish tissues was determined by immunodiffusion methods. gamma was specific to brain. The beta protein cross-reacted but was not identical to a widely distributed substance in plasma, liver and kidney. Both beta and gamma appear to be species specific in that no cross-reactivity was obtained with mouse, chick or rat brain proteins. Immunological methods, in combination with double labeling experiments were used to establish that the beta and gamma antigens were proteins which were normally present in goldfish brain. Both the beta and gamma antisera were equally capable of specifically precipitating the proteins which were differentially labeled after training as well as purified proteins of the same molecular weight present in the brains of control animals. These results suggest that the acquisition of a new pattern of behavior can increase the demand for the synthesis of specific proteins (beta and gamma) normally present in goldfish brain.

Animals↗
PubMed1977

Brain protein metabolism and the acquisition of new patterns of behavior.

Three cytoplasmic proteins (designated alpha, beta and gamma) in the goldfish brain consistently incorporated more labeled valine in animals that had acquired a new pattern of swimming behavior than in untrained animals. The changes were identified by double labeling techniques ([3H]valine injected into trained experimental animals and [14C]valine into untrained controls) and by gel-electrophoresis. Goldfish tested in a variety of control behavioral situations showed no detectable protein changes. The migration properties of alpha, beta, and gamma correspond to proteins having molecular weights of 37,000, 32,000, and 26,000, respectively. Two of the proteins (beta and gamma) were isolated, purified, and injected into rabbits. The antisera thus obtained were used: (i) to establish that the proteins are normal components of goldfish brain; (ii) to inhibit long-term retention of the behavior; and (iii) to demonstrate by immunofluorescence methods that the beta and gamma proteins are localized in certain cells at specific brain regions.

Animals↗
PubMed1976

Identification of specific changes in the pattern of brain protein synthesis after training.

Double labeling studies with [3H]valine and [14C]valine were used to investigate the pattern of protein synthesis in the brains of goldfish. The protein fractions in three bands (alpha, beta, and gamma) on sodium dodecyl sulfate-polyacrylamide gels indicate that more valine was incorporated in the brains of goldfish that had been trained in a vestibular conditioning task than in the brains of untrained fish or fish trained in a variety of control behavioral situation. Changes in the pattern of labeling were localized in the cytoplasmic fraction of the brain; no increases in labeling occurred in either the nuclear or synaptosomal components. The results suggest that a specific change occurs in the pattern of protein synthesis in the brain after the acquistion of a new behavior.

Age Factors↗
PubMed1976

Brain metabolism and the acquisition of new behaviors. I. Evidence for specific changes in the pattern of protein synthesis.

The pattern of incorporation of labeled valine into goldfish brain proteins was compared for animals trained in a new swimming skill with controls. Double labeling studies followed by electrophoretic separation of the proteins on SDS-polyacrylamide gels, showed that there was a consistent increase of valine incorporation for the trained animals at 3 band positions on the gels. These alpha, beta, andnu bands correspond to molecular weights of 37,000, 32,000 and 26,000 daltons. The protein changes were confined to the brain cytoplasmic fraction, in that they were absent from the brain nuclear, brain synaptosomal, and kidney cytoplasmic proteins. Such protein changes were not obtained for a variety of control behavioral situations. The results suggest that there is higher rate of synthesis of specific proteins in goldfish brain following the acquisition of a new pattern of behavior.

Animals↗
PubMed1973

Seasonal changes in the learning and activity patterns of goldfish.

Goldfish exhibit cyclic changes with an annual rhythm in their learning and activity patterns. Maximum learning ability and active behavior occurred during the months of January, February, and March. Poor learning was obtained in the summer months, after the onset of the spawning season. The results indicate that the annual periodic changes of the hormonal levels which govern spawning may also influence learning and activity patterns.

Animals↗
PubMed1971

Dibutyryl adenosine cyclic 3':5'-monophosphate effects on goldfish behavior and brain RNA metabolism.

Intraventricular administration of dibutyryl adenosine cyclic 3':5'-monophosphate into goldfish brains produced hyperactive animals. A study of the effects of the drug (25-50 mg/kg) on the incorporation of [5-(3)H] orotic acid, as a precursor of labeled uridine and cytidine, into newly synthesized RNA showed the formation of an RNA with a uridine to cytidine ratio 20-50% higher than that of the control. In double-labeling experiments with uridine as the labeled precursor, the synthesis of a nuclear RNA fraction (not produced in the absence of drug) was demonstrated. Some of this RNA was found to migrate into the cytoplasmic fraction and to become associated with polysomes. The results suggest that cyclic AMP might function as a "metabolic demand signal" for eliciting new RNA synthesis in goldfish brain.

Animals↗
PubMed1970

RNA metabolism in goldfish brain during acquisition of new behavioral patterns.

Base composition measurements were used as a criterion of RNA changes in goldfish brain. RNA synthesized during the acquisition of new swimming skills was found to have a uridine/cytidine ratio 20-80 per cent higher than that of RNA formed under nonlearning conditions. A variety of behavioral situations were used to demonstrate that these RNA changes were not due to such factors as intense physical exertion, passive responses to stress, or the intense electrical activity of the brain and convulsive behavior produced by KCl injections. The RNA changes were produced by two behavioral situations; (1) during the process of acquiring new swimming skills, and (2) as a result of attempts to master an impossible task. The results suggest that the modified RNA synthesis taking place during the acquisition of new behavioral patterns is probably not specific as to the particular information content being stored, but may be required for the consolidation step of new information storage.

Animals↗
PubMedDate not supplied

The role of ependymin in the development of long lasting synaptic changes.

1.) Three types of training experiments (a complex motor task, avoidance conditioning and classical conditioning) in the goldfish and one in the mouse (T-maze learning) indicate that the brain extracellular glycoprotein (ependymin) has a role in the consolidation process of long-term memory formation. 2.) Direct ELISA measures of the concentration of ependymin in the brain extracellular fluid (ECF) indicate that its level decreases after goldfish learn to associate a light stimulus (cs) with the subsequent arrival of a shock (US): paired CS-US gave changes whereas an unpaired presentation of CS-US gave no changes in comparison to unstimulated controls. 3.) Ependymin is released into ECF and CSF as mixtures of three types of disulfide-linked dimers of two acidic polypeptide chains (M. W. 37 kDa and 31 kDa). It contains 10% carbohydrate as an N-linked glycan. 4.) Ependymin has the capacity to polymerize in response to events that deplete Ca2+ from the brain extracellular environment. A molecular hypothesis relating polymerization properties to the process of formation of long-lasting synaptic changes is proposed. 5.) Investigations of the pattern of regeneration of goldfish optic nerve and the mechanisms of long-term potentiation (LTP) of rat brain hippocampal slices suggest that ependymin has a role in the formation of long-lasting synaptic changes. The E.M. data show that polymerized products which stain with anti-ependymin sera accumulate at synapses and in new spines after LTP.

Animals↗