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Biomedical subjects

J Elliott

Publications and source records attributed to J Elliott.

At least 235 records · Page 13Linked to original sources

Opiatelike actions of eseroline, an eserine derivative.

Eseroline, an eserine derivative without anticholinesterase activity, was tested in several systems for opiatelike activity. Eseroline depressed the twitch of the field-stimulated guinea pig ileum myenteric plexus longitudinal muscle preparation but failed to depress the twitch of the rat vas deferens. Intraperitoneal injections of eseroline in rats induced naloxone-antagonizable analgesia and catalepsy. Eseroline failed to influence the release of acetylcholine from the cortex of anesthetized rats. These observations have implications for studies in which eserine is used as a pharmacological tool.

Acetylcholine↗

Action of coenzyme A on adenine derivative receptors in isolated tissues.

The action of Coenzyme A (CoA) was investigated on the mechanical activity of four isolated tissues known to possess adenine derivative (AD) receptors that are sensitive, or resistant to blockade by theophylline. CoA produced a dose-related inhibition of the electrically stimulated myenteric plexus longitudinal muscle of the guinea pig ileum, and of the spontaneously contracting rabbit ileum. This effect was competitively antagonized by theophylline in both tissues. CoA caused a dose-related relaxation of the rat ileum. Low doses of CoA were not antagonized by theophylline but higher doses were antagonized by this drug. The rabbit detrusor, which was contracted by ATP and ADP, was not affected by CoA. Differences in the action of CoA at AD receptors in these four tissues, and in its antagonism by theophylline reflect a heterogeneity of these receptors. It is suggested that the simple sub-division of adenine derivative receptors into two types may be inappropriate.

Adenine↗

Purification of Torpedo californica post-synaptic membranes and fractionation of their constituent proteins.

A rapid methof for preparation of membrane fractions highly enriched in nicotinic acetylcholine receptor from Torpedo californica electroplax is described. The major step in this purification involves sucrose-density-gradient centrifugation in a reorienting rotor. Further purification of these membranes can be achieved by selective extraction of proteins by use of alkaline pH or by treatment with solutions of lithium di-idosalicylate. The alkali-treated membranes retain functional characteristics of the untreated membranes and in addition contain essentially only the four polypeptides (mol.wts. 40000, 50000, 60000 and 65000) characteristic of the receptor purified by affinity chromatography. Dissolution of the purified membranes or of the alkali-treated purified membranes in sodium cholate solution followed by sucrose-density-gradient centrifugation in the same detergent solution yields solubilized receptor preparations comparable with the most highly purified protein obtained by affinity-chromatographic procedures.

Alkalies↗