Search PubMed⌕ Search

Biomedical subjects

G B Frank

Publications and source records attributed to G B Frank.

At least 73 records · Page 4Linked to original sources
PubMed1971

Blockade of the reticulospinal inhibitory pathway by anaesthetic agents.

1. Adult cats were decerebrated at the intercollicular level. The effect of the anaesthetic agents, pentobarbitone, paraldehyde, tribromethanol, chloralose and procaine on the reticulospinal inhibitory pathway, which produced inhibition of segmental reflex potentials, was analysed.2. The doses which blocked this inhibitory pathway did not exceed the doses required to produce surgical level anaesthesia with any of the drugs.3. After the reticular inhibition of the reflex potentials was abolished, the reflex potentials were augmented by reticular stimulation with a higher intensity. This was thought to be due to spread of current to the excitatory pathways which were not completely depressed by the anaesthetic agent.4. The resistance of the reticular facilitation of the reflex potentials to inhibition by these drugs after abolition of inhibition corresponded in general to the degree of excitement in intact mice produced by the same drugs.5. These findings seem to indicate that the preferential block of the reticulospinal inhibitory pathway may be an important neural mechanism for the excitement stage of anaesthesia.

Action Potentials↗
PubMed1970

Effects of drugs acting alone and in combination on the motor activity of intact mice.

1. When administered to intact white mice, the central depressants-diphenhydramine, promethazine, chlorpromazine, gammahydroxybutyrate, gammabutyrolactone, hyoscine, and pethidine-produced sedation in small doses, but excitement and convulsions in higher doses. When given to mice pretreated with subanaesthetic doses of phenobarbitone these drugs abolished the righting reflex both in convulsant doses (hyoscine excepted) and in non-convulsant doses. These effects are similar to the effects previously observed with local anaesthetics.2. Meprobamate, diazepam and chlorpromazine produced a loss of righting reflex both when given alone and following phenobarbitone. When given alone in higher doses, chlorpromazine induced convulsions.3. The central stimulants bemegride and picrotoxin antagonized the loss of righting reflex produced by phenobarbitone, but nikethamide, caffeine and strychnine did not alter the depressant effects of phenobarbitone.4. On the basis of these and previous studies with intact white mice a tentative classification of drugs having generalized depressant and stimulant effects on the central nervous system was proposed and discussed.

Adjuvants, Anesthesia↗
PubMed1970

Effects of general depressant drugs on the electrical responses of isolated slabs of cat's cerebral cortex.

1. In the neuronally isolated cortex of the cat, local application of diphenhydramine, promethazine, gammahydroxybutyrate, gammabutyrolactone, gamma aminobutyric acid, hyoscine and pethidine, and the intravenous injection of diazepam and meprobamate depressed or abolished the surface negative and surface positive response to direct stimulation and raised the stimulus threshold of the positive burst response. These effects were the same as previously demonstrated for general and local anaesthetics on the same preparation.2. Chlorpromazine produced a similar depression in small concentrations but caused spontaneous activity in higher concentrations.3. In contrast to local application, pethidine when given by intravenous injection in a high dose produced convulsant activity in the isolated cortical slab. The possibility was suggested that the convulsant activity was produced by a metabolite of pethidine.4. The results of this investigation suggest that the central depression produced by a number of structurally unrelated drugs is indicative of an anaesthetic-like property of these drugs.

Action Potentials↗
PubMed1970

Effects of general stimulant drugs on the electrical responses of isolated slabs of cat's cerebral cortex.

1. In the neuronally isolated cortex of the cat, local application of bemegride, picrotoxin, nikethamide, caffeine and strychnine facilitated the surface positive response of the isolated cortex and lowered the stimulus threshold for this response. Excepting nikethamide, they all produced convulsive discharge in the isolated cortex unrelated to the applied stimulus.2. Local application of glutamate to the cortex produced spreading depression, which was sometimes preceded by spontaneous positive bursting.3. In contrast to the "general depressants" which produce a relatively consistent pattern of effects on the electrical responses of isolated cortex, the "general stimulants", although they all have excitatory effects on isolated cortex, each produced a greatly different type of electrical response in the isolated cortex, suggesting that several different mechanisms of action are responsible for their effects.

Action Potentials↗