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Biomedical subjects

J D Morrison

Publications and source records attributed to J D Morrison.

At least 73 records · Page 4Linked to original sources
PubMed1977

The generation of nerve and muscle repetivie activity in the rat phrenic nerve-diaphragm preparation following inhibition of cholinesterase by ecothiopate.

1 Simultaneous extracellular recordings were made from two end-plate zones of the isolated diaphragm and from the phrenic nerve of the rat in response to stimulation of the nerve. The contractions of the diaphragm were also recorded.2 In the curarized diaphragm, the introduction of ecothiopate, a non-competitive inhibitor of cholinesterase, caused a threefold increase in the amplitude of the end-plate current and an eightfold increase in the duration at half the peak amplitude.3 In the non-curarized diaphragm, the introduction of ecothiopate caused the generation of repetitive activity (RA) in first the phrenic nerve: this was then followed by RA in the diaphragm. At that stage, nerve RA possessed a shorter latency than muscle RA. The generation time for nerve RA was 1.6 ms and for mRA, it was 2.7 milliseconds.4 Nerve RA was more labile than muscle RA; it was readily abolished by increasing the frequency of stimulation, by magnesium, by tubocurarine or by high concentrations of ecothiopate, whereas muscle RA was still generated. Steady exposure to acetylcholine abolished both forms of RA.5 Two competitive inhibitors of cholinesterase, neostigmine and ambenonium, were also shown to evoke RA in nerve and muscle. The generation times for nerve RA and muscle RA were similar to those following ecothiopate.6 It was concluded that nerve RA and muscle RA were generated after the inhibition of cholinesterase by ecothiopate as a result of the prolonged action of acetylcholine upon cholinoceptive sites on the nerve terminal and motor endplate respectively. A direct excitatory action of ecothiopate upon the phrenic nerve terminals was excluded.

Acetylcholine↗
PubMed1975

A comparison of the efficacy of cyclizine and perhenazine in reducing the emetic effects of morphine and pethidine.

1 The ability of cyclizine (50 mg) and perphenazine (2.5 and 5.0 mg) to counteract the emetic effects of pethidine (100 mg) and morphine (10 and 15 mg) was compared in women undergoing a standard minor operation with a standard anaesthetic. 2 Perphenazine (5.0 mg) was as effective an anti-emetic as cyclizine (50 mg) and both were more effective than perphenazine (2.5 mg). 3 The reduction in vomiting and nausea by cyclizine (50 mg) and perphenazine (5 mg) was approximately the same following pethidine (100 mg) and morphine (10 mg) but much less against the larger dose of morphine. 4 Both anti-emetics had a rapid onset of action but their anti-emetic activity did not last as long as the emetic effect of morphine. 5 Perphenazine (5 mg) was accompanied by an unacceptably high incidence of restlessness. 6 In clinical practice cyclizine (50 mg) is preferred to perphenazine (5 mg) as an anti-emetic.

Antiemetics↗
PubMed1971

Controlled comparison of the efficacy of fourteen preparations in the relief of postoperative pain.

Thirteen analgesic drugs, four of them at two dose levels, four analgesics in combination with antagonist or neuroleptic agents, and saline have been evaluated simultaneously in the relief of postoperative pain. The method of assessment was designed to favour drugs which provided freedom from pain with minimum depression of consciousness. Only levorphanol 2 mg proved significantly superior to pethidine 100 mg, which was used as the standard reference drug. Oxycodone 10 mg, pentazocine 20 mg, and the morphine 10 mg and cyclizine 50 mg combination were the most successful of the remaining drugs. None of the drug combinations was significantly better than the analgesic drug given alone.

Abdomen↗