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Biomedical subjects

G Ellison

Publications and source records attributed to G Ellison.

87 records · Page 5Linked to original sources
PubMed1977

A slow-release silicone pellet for chronic amphetamine administration.

A slow release amphetamine pellet consisting of a silicone capsule containing d-amphetamine base in polyethylene glycol is described. When implanted s.c. in rats this pellet produces brain levels initially comparable to an i.p. dose of 2 mg/kg of d-amphetamine sulfate; these levels gradually fall but appreciable amphetamine remains present in the brain for over 10 days. Rats implanted with these pellets exhibit sustained motor stereotypies and constant hyperactivity in stabilimeters for 2-3 days. Four days after implantation activity declines to near control levels even though amphetamine is still present in the brain. During this later stage rats show exaggerated startle responses and resist handling. This pellet is a unique tool for the study of the behavioral and physiological effects of prolonged amphetamine intoxication.

Amphetamine↗
PubMed1977

Opposed effects of locus coeruleus and substantia nigra lesions on social behavior in rat colonies.

Rats were observed in enriched colony environments following radio-frequency lesions of the locus coeruleus (LC), zona compacta of substantia nigra (SN, or control operations. LC-lesioned animals were initially inactive, stayed in the burrows, and fell when climbing ropes and ramps. SN-lesioned rats were opposite to LC animals in many ways. They were hyperactive, had minimal motor disturbances, and were hyperaggressive. SN animals self-isolated and were not social-groomers, whereas LC rats socially-groomed and mounted other animals more than controls. These results provide evidence that the dopaminergic nigrostriatal pathway and the noradrenergic fibers innervating the cerebral cortex and limbic forebrain exert opposed effects upon behavior.

Aggression↗
PubMed1977

The association of HLA antigens A3, B7, and DW2 with 330 multiple sclerosis patients in the United States.

Reported associations of HLA antigens with MS have varied considerably. In this study we have examined 330 clinically definite MS patients from the United States. The frequency of DW2 (52%) was highly statistically significant in MS patients as compared to controls (p less than 0.00001). Neither A3 nor B7 was significantly increased in MS; however, the joint occurrences of A3-DW2 (20% vs 7%, p less than 0.001) and B7-DW2 (30% vs 13%, p less than 0.0002) are highly associated with MS.

Chromosome Mapping↗
PubMed1977

Subclinical eye movement disorders in patients with multiple sclerosis.

Eye movements were quantitatively evaluated in 16 patients with well-documented multiple sclerosis who had minimal or no clinically apparent eye movement disorder. Induced saccade and pursuit eye movements were recorded with electro-oculography and analyzed with newly developed programs on a laboratory digital computer. Thirteen of the 16 patients had significant (p less than 0.05) impairment of saccades and/or smooth pursuit when compared with 25 normal subjects tested in our laboratory. The type and frequency of abnormalities were as follows: saccade dysmetria, eight; delayed saccade reaction time, five; bilateral saccade slowing, four; slowing of adducting saccades only (medial longitudinal fasciculus syndrome), one; and impaired smooth pursuit, both directions, three, and one direction only, three. In addition, four patients had vestibular nystagmus with eyes closed, and one patient had typical rebound nystagmus. These data suggest that quantitative assessment of eye movements in patients with suspected multiple sclerosis can help in identifying the important "second lesion."

Adult↗
PubMed1976

Monoamine neurotoxins: selective and delayed effects on behavior in colonies of laboratory rats.

Male laboratory rats were raised in two colonies, each of 27 rats, and then given intraventricular injections of the norepinephrine neurotoxin 6-hydroxydopamine (6-OHDA) or the serotonin neurotoxin 5,6-dihydroxytryptamine (5,6-DHT) or saline. They were then returned to their enclosure and behavior during the next 50 days was observed. Shortly after neurotoxin injections the 6-OHDA rats spent more time in the burrows than controls and when out were inactive. The 5,6-DHT rats in contrast spent more time in the open than controls, ran more in activity wheels, approached humans, and fought more. Fighting, mounting, and hoarding in the colony gradually increased for 25 days; during this time the status of the 6-OHDA animals fell progressively whereas the 5,6-DHT animals increased in dominance. Social behavior returned to more normal levels after 50 days. Several successive stages of behavioral alterations occur following neurotoxin injections.

Aggression↗
PubMed1976

Exaggerated avoidance of novel stimulation in rats partially recovered from central norepinephrine damage.

Rats in which central norepinephrine lesions are made with 6-OHDA and a recovery period allowed show a behavioral syndrome distinct from controls, from rats with more extensive norepinephrine damage (lesioned with 6-OHDA, allowed to recover, and relesioned), and from rats with general depletion of serotonin (chronic PCPA). These rats administered central 6-OHDA injections and then allowed a recovery period rear less in open field than all other groups and are characterized by an exaggerated avoidance of novel visual stimulation in light onset and light escape tests. It is proposed that this reflects the hyperresponsivity of partially repaired, supersensitive norepinephrine circuitry to novel or intense stimulation.

Animals↗
PubMed1976

The aging psychiatric hospital: an approach to humanistic redesign.

Since funds for the construction of new treatment facilities are scarce, outmoded wards must be redesigned to meet the current needs of users. The authors feel the redesign must integrate modern therapeutic concepts, humanistic patient requirements, and pragmatic budgetary limitations. They review current theory about the effects of the physical environment on behavior, and they discuss such questions as to what extent the need for security should govern ward design and how pleasant the environment should be. They also describe a specific redesign for a 32-bed psychiatric ward of a large federal hospital constructed in the early 1950s.

Hospital Design and Construction↗
PubMed1975

Cholinergic modulation of an opposed effect of d-amphetamine and methylphenidate on the rearing response.

Rats given d-amphetamine (1 mg/kg) engage in frequent, short-duration rearing responses, whereas rats given methylphenidate (1 mg/kg) make less frequent, long-duration responses. The effects on this behavior of mixing d-amphetamine or methylphenidate with scopolamine or physostigmine suggest that this opposed action on rearing response duration is related to cholinergic-catecholaminergic balance. The anticholinergic agent scopolamine produces changes in rearing response duration similar to those produced by d-amphetamine, while the cholinergic agent physostigmine lengthens response duration and further potentiates this effect of methylphenidate.

Animals↗
PubMed1975

Learning deficits in rats with malnourished grandmothers.

Female rats (F0) were maintained on a protein-restricted or a normal diet 1 month prior to mating and throughout pregnancy. Their female offspring (F1) were maintained on a normal protein diet and mated with normal males. In previously reported studies, the 2nd generation offspring (F2) of the malnourished rats have been found at birth to have significantly lower cerebral DNA ( a measure of cell number), cerebral weight, and cerebral protein than normal controls. We now report that these F2 animals show marked learining deficits at maturity on 2 different successive reversal tasks, even though they themselves have never directly experienced malnutrition. Thus, certain behavioral as well as biochemical effects of malnutrition appear to the next generation of animals.

Animals↗
PubMed1975

Serum linoleic acid in multiple sclerosis.

Total serum fatty acids were analyzed in 30 patients with multiple sclerosis and in 33 controls. No significant decrease in linoleic acid was found in the patients with multiple sclerosis. A disturbance in linoleic acid metabolism is not inevitably associated with this disease.

Adult↗
PubMedDate not supplied

Tricyclic antidepressants: effects on extinction and fear learning.

Rats trained to run an alley for a food reward were extinguished following injections of different antidepressants. When retested several days later, the animals extinguished following pretreatment with the NE reuptake blocker protriptyline showed faster running speeds than did the other groups. Other rats given electrical shocks following pretreatment with protriptyline avoided the compartment in which they had been shocked less than did animals shocked following pretreatment with other antidepressants. This implies an interferance with some aspect of the learning or consolidation process which is correlated with the degree of NE reuptake blockage. It is hypothesized that NE terminals are deactivated following frustrative nonreward or punishment by the conversion and reuptake of the released NE to an altered extinction molecule.

Animals↗