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Biomedical subjects

A Cherkin

Publications and source records attributed to A Cherkin.

54 records · Page 3Linked to original sources
PubMed1969

Kinetics of memory consolidation: role of amnesic treatment parameters.

The consolidation theory states that with the passage of time the engram of a recent learning experience grows increasingly resistant to disruption by amnesic treatment. The time required to reach complete resistance ("consolidation time") is a controversial issue; current estimates range from 10(1) to 10(5) seconds. The present study suggests a parsimonious interpretation of the divergence, namely, that weak amnesic treatments fail to block memory consolidation but do slow its rate, so that post-treatment consolidation inflates the retention scores measured 24 hours later and leads to variably shortened "consolidation times."This study utilized 2880 neonate chicks trained in a one-trial avoidance paradigm. Retrograde amnesia was induced by treatment with flurothyl (CF(3)CH(2)-OCH(2)CF(3)) vapor. Apparent "consolidation times" determined by conventional data analysis varied widely as a function of flurothyl concentration and exposure time, ranging from 4 minutes under weak amnesic conditions (0.85% flurothyl; 1-min exposure) to 24 hours under strong conditions (1.7% flurothyl; 8-min exposure). With 1.7% flurothyl, the consolidation half-time was found to be 9.8 hours.

Amnesia↗
PubMedDate not supplied

L-prolyl-L-arginyl-glycineamide induces memory enhancement in chicks.

Two-day-old chicks were injected either intraventricularly or intraperitoneally with saline or a L-prolyl-L-arginyl-glycineamide solution. This C-terminal tripeptide of arginine vasopressin produced dose dependent enhancement effects when injected centrally but not peripherally. Physical debilitation and/or aversive effects of the peptide were eliminated as the cause of the decreased responding noted in memory enhancement studies using this avoidance paradigm. Possible memory mechanisms are discussed in light of this peptide's relationship to vasopressin, vasotocin, and L-propyl-L-leucyl-glycineamide.

Analysis of Variance↗
PubMedDate not supplied

The effects of adrenergic, opioid and pancreatic polypeptidergic compounds on feeding and other behaviors in neonatal leghorn chicks.

The present study examined the effects of intracerebral (IC) administration of pancreatic polypeptide (PP), neuropeptide Y (NPY), norepinephrine (NE), dynorphin and naloxone on food intake in 2-day-old Leghorn chicks. Of the compounds studied, only PP (20 micrograms) and naloxone (10 and 20 micrograms) elevated food intake significantly as compared to saline injections. NPY, a potent orexigenic agent in mammals, did not elevate consumption significantly in a dose-related fashion. This latter finding was attributed to the occurrence of tonic-clonic convulsions following NPY administration. However, for those chicks which did not exhibit behavioral convulsions, food intake appeared to be elevated by 1, 5 and 10 micrograms of NPY. Similarly, NE did not elevate food intake but instead induced sedation and narcolepsy, a behavioral response which could be distinguished from the convulsions observed after NPY. In a separate group of chicks, the effect of NPY on cortical activity was examined. Bipolar electrodes were used to record EEG activity before and after IC injections of saline, NPY or NE. The behavioral convulsions induced by NPY corresponded with an increase in high amplitude sharp-wave activity, which persisted for up to 30 min post-injection. Collectively, these results suggest that the neurochemical substrates for feeding in 2-day-old Leghorn chicks are distinct from those underlying food intake in adult mammals.

Animals↗
PubMedDate not supplied

Effect of acute arecoline, tacrine and arecoline + tacrine post-training administration on retention in old mice.

The amnesias characteristic of Alzheimer's disease and other age-related dementias are refractory to conventional pharmacotherapy. A recent treatment strategy is to combine drugs to improve their memory enhancing effect. We previously reported that in young weakly trained mice, the combination of arecoline and tacrine was more effective on a mg/kg basis than either drug administered alone. This was true whether the route of administration was intracerebroventricular, subcutaneous or oral. We now report that 24 month old mice trained to avoid footshock in a T-maze show poor retention when tested one week later. Subcutaneous administration of arecoline, tacrine (also referred to as tetrahydroaminoacridine, THA) and arecoline plus tacrine administered immediately after T-maze footshock avoidance training enhanced retention of 24 month old mice compared to the saline-injected control. Since the combination was as effective as the single drug treatments even though 96% less arecoline and 99.7% less tacrine was administered, the combination showed marked potentiation of drug action of memory processing.

Aging↗