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Biomedical subjects

I Creese

Publications and source records attributed to I Creese.

At least 109 records · Page 6Linked to original sources
PubMed1979

Species variation in dopamine receptor binding.

Binding of 3H-spiroperidol, 3H-apomorphine and 3H-ADTN (2-amino-6,7-dihydroxytetrahydronaphthalene) associated with dopamine receptors has been evaluated in corpus striatal membranes of calf, rat and human brains. Substantial species differences are apparent for numberous agonists and antagonists in competing for receptor binding. In general, dopamine receptor antagonists are more potent in rat and agonists more potent in calf. In competing for 3H-spiroperidol binding sulpiride, molindone and metaclopramide show the most pronounced species differences, being 3--10 times more potent in rat and human than in calf. In all three species agonists compete for 3H-spiroperidol binding with Hill coefficients less than one while antagonists inhibit 3H-spiroperidol binding with Hill coefficients of about 1.0. Conversely, 3H-apomorphine and 3H-ADTN binding in all three species is inhibited by antagonists with Hill coefficients less than 1.0 while agonists display Hill coefficients of about 1.0. In general agonists are more potent in competing for binding of 3H-apomorphine and 3H-ADTN than 3H-spiroperidol. However, a small component of dopamine, apomorphine and ADTN inhibition of 3H-spiroperidol binding displays very high affinity (IC50 about 1 nM). In human amygdala 3H-spiroperidol appears to label serotonin receptors predominantly.

Animals↗
PubMed1979

Opiate receptor binding affected differentially by opiates and opioid peptides.

The potencies of various opiates in displacing several 3H-opiate ligands' binding to rat membranes vary depending on the nature of the ligand. Whereas opiate antagonists, as well as the opioid peptides and some agonists (etorphine, levorphanol and phenazocine) display similar affinities in displacing either 3H-opiate or 3H-methionine enkephalin binding, other agonists (such as morphine and oxymorphone) are considerably (20-50 times) weaker in displacing 3H-enkephalin than 3H-dihydromorphine binding. These agonists also compete for 3H-enkephalin binding with shallow displacement curves, and are greatly weakened in displacing 3H-naloxone binding in the presence of sodium. These agonists differ from the other opiate classes by possessing a relatively hydrophilic component in their C-ring moieties which may provide a basis for the differential interactions of drugs with the opiate receptor.

Animals↗
PubMed1979

Serum levels of neuroleptics measured by dopamine radioreceptor assay and some clinical observations.

A new dopamine radioreceptor assay was used to measure serum concentrations of neuroleptics during treatment of 58 patients. Results of this assay are expressed as chlorpromazine equivalents. Serum concentrations varied with different drugs, with extremely high levels in patients receiving thioridazine or mesoridazine. No detectable serum levels were found in 11 patients, probably either due to low drug doses or noncompliance in taking medication. Best results with the assay were obtained in the 22 patients treated with haloperidol. Serum concentrations of haloperidol were correlated with dose and were related to the Brief Psychiatric Rating Scale (BPRS) total pathology score, as well as to BPRS factor scores for thinking disturbance and paranoid disturbance. Serum concentrations of haloperidol were not different among patients with or without the presence of extrapyramidal symptoms or among patients receiving or not receiving concurrent antiparkinson medication.

Antipsychotic Agents↗
PubMed1978

3H-Apomorphine interactions with dopamine receptors in calf brain.

3H-apomorphine binds to membranes from areas of the corpus striatum and limbic system of calf brain saturable and with a drug specificity indicating that it labels dopamine receptors. In terms of drug specificity, log-logit displacement curve slopes and number of binding sites, 3H-apomorphine interacts with receptors in a manner more like 3H-dopamine than 3H-haloperidol. These properties of 3H-apomorphine binding are those of an apparently "pure" agonist in contrast to the partial agonist effects of apomorphine upon the dopamine-sensitive adenylate cyclase.

Animals↗