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Biomedical subjects

L Ahtee

Publications and source records attributed to L Ahtee.

At least 109 records · Page 6Linked to original sources
PubMed1973

The effect of narcotic analgesics on the uptake of 5-hydroxytryptamine and (-)-metaraminol by blood platelets.

1. The effects of narcotic analgesic and related drugs were studied on the uptake of 5-hydroxytryptamine (5-HT) and (-)-metaraminol by blood platelets.2. The most potent drug in inhibiting the uptake of 5-HT (10 muM) by human platelets was methadone, followed by pentazocine>piminodine approximately pethidine approximately anileridine approximately cyclazocine approximately thebaine > dextropropoxyphene. Alphaprodine, papaverine, apomorphine, nalorphine, codeine, and morphine were almost without effect. Methadone was slightly less active than desipramine, and had 10% of the activity of imipramine under similar conditions. Naloxone did not antagonize the effect of methadone on 5-HT uptake.3. The most potent inhibitor of metaraminol (3 muM) uptake by human platelets was piminodine, followed by pentazocine>/=anileridine>cyclazocine=methadone > dextropropoxyphene approximately thebaine >/= papaverine approximately alphaprodine >pethidine>morphine. The activity of morphine was 1% of that of piminodine. Piminodine was more potent than desipramine and protriptyline under similar conditions. The order of potency of drugs studied in inhibiting the uptake of metaraminol by rabbit platelets was similar to that obtained with human platelets.4. The effects of the analgesics studied on inhibiting uptake of monoamines did not correlate with their pain-relieving properties.

Alphaprodine↗
PubMed1970

The effect of benzodiazepines and atropine on exploratory behaviour and motor activity of mice.

1. Male albino mice were watched in red light on a tunnel board to test exploration and their motor activity was assessed in an open cage, 30 min after intraperitoneal injection of drugs.2. Atropine and methylatropine 5 or 10 mg/kg did not alter the motor activity of the mice, while chlordiazepoxide 25 or 50 mg/kg and diazepam 10 or 20 mg/kg increased the activity, especially at the lower of the two doses used.3. All the compounds used except methylatropine adversely affected the exploratory behaviour.4. When atropine 10 mg/kg was given with the benzodiazepines, the activity of the mice was reduced and exploratory behaviour was further impaired. Methylatropine did not have this effect.

Animals↗
PubMed1970

Acid metabolites of monoamines in avian brain; effects of probenecid and reserpine.

1. The concentration of the dopamine (DA) metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the anterior part of the nucleus basalis of pigeon brain was found to be 0.17 +/- 0.01 mug/g, which is about one-fifth of the concentration of homovanillic acid (HVA) in this region. In the chicken, the concentration of HVA in the (entire) nucleus basalis was 0.06 +/- 0.006 mug/g, lower than in any other species examined, and giving a ratio of DA to HVA of about 50. The concentration of DOPAC in the 8 day old chick was 0.053 +/- 0.002 mug/g.2. Probenecid, 200 mg/kg intramuscularly, doubled the content of DOPAC in the nucleus basalis of the pigeon and increased the concentration of HVA in both the pigeon and the chicken by a factor of 4 to 5. These findings demonstrate the existence, in avian brain, of an active transport mechanism for the removal of acidic substances and explain the low concentrations of the acids found in bird brain.3. A method is described for the estimation of 5-hydroxytryptamine (5-HT) and 5-hydroxyindolylacetic acid (5-HIAA) in the same tissue sample. Probenecid caused an increase in the 5-HIAA content but produced no change in the 5-HT content of the nucleus basalis of pigeon brain.4. Reserpine caused a fall in the content of acidic DA metabolites in the nucleus basalis of the pigeon. The effect was more pronounced after raising the concentration of these acids with probenecid.5. Treatment of pigeons with pargyline (100 mg/kg 17 hr before decapitation) did not significantly increase the DA content of the nucleus basalis, but it prevented to some extent the loss in DA caused by reserpine.6. Pigeons and chickens were sedated by probenecid. The deepest sedation occurred at about the same time as the greatest increase in the acidic amine metabolites in the brain.7. Intracisternal injection of HVA in the pigeon and intravenous injection of large amounts of HVA, DOPAC, 5-HIAA or 3,4-dimethoxyphenylacetic acid into newly hatched chicks did not produce any sedation or other effects on behaviour. In contrast, injection of sodium gamma-hydroxybutyrate caused paralysis followed by prostration and eye closure.8. Estimation of the concentration of HVA in the brain of the young chick after intravenous injection of the acid (100 mg/kg) showed that the concentration was of the same order of magnitude as it is in animals given probenecid; this suggests that the sedation which follows probenecid is not related to the accumulation of acidic amine metabolites.

Animals↗