Comparison of bicyclic phosphorous esters with bicuculline and picrotoxin as antagonists of presynaptic inhibition in the rat cuneate nucleus

Summary The effects of 2 of a series of bicyclic phosphorous esters, the ethyl (EPTBO) and isopropyl (IPTBO) compounds, were compared with those of the GABA antagonists, picrotoxin and bicuculline, on presynaptic inhibition in the rat cuneate nucleus. Both EPTBO and IPTBO were found to be effective, reversible antagonists of presynaptic inhibition, with IPTBO approximately 10 times more potent than EPTBO and equipotent with bicuculline, EPTBO equipotent with picrotoxin.The authors are grateful to Dr J. F. Collins, Department of Chemistry, Sir John Cass School of Science and Technology, 31 Jewry Street, London, for the gift of bicyclic phosphorous esters.     

The identification of norlobariol,a new lichen constituent fromXanthoparmelia scabrosa (Tayl.) Hale

Summary Norlobariol (I) previously described as a synthetic product derived from norlobaridone (II) was isolated as a new metabolite fromXanthoparmelia scabrosa (Tayl.) Hale.Acknowledgment. The authors wish to acknowledge the assistance of Dr D. Galloway in identifying the lichen sample and Dr A.W. Campbell for the microanalytical data.     

Uptake of exogenous protein by supraependymal cells of the feline area postrema.

Supraependymal cells occurring on the surface of the feline area postrema were examined for phagocytic ability. It was shown that they could ingest exogenous horseradish peroxidase that was experimentally introduced into the brain ventricular system. The cells thus bear functional as well as ultrastructural attributes of macrophages, similar to those found in the third ventricle and subarachnoid space.     

Activation of aldosterone and renin secretion by thermal stress

Résumé Un stress thermique aigu est un activateur rapide et puissant de la sécrétion du système rénineangiotensine et de l'aldosterone au cours d'une alimentation normo ou hyposodée, et peut être utilisé pour mesurer l'intégrité des systèmes de production de ces hormones.     

Histochemical evidence for a somatotopic organization of the rubrospinal projection in the rat

Résumé La technique de l'acétylthiocholine démontrant l'activité de l'acétylcholinesterase fût employée pour indiquer la perte régionale d'enzyme des cellules nerveuse du noyau rouge du rat à la suite d'une lésion du faisceau rubrospinal. Les lesions aux niveaux thoraciques inférieurs du cordon médullaire donnent lieu à une perte d'enzyme des cellules dans la partie ventrale de la moitié caudale du noyau rouge. Cependant, les lésions du faisceau aux niveaux cervicaux du cordon médullaire donne lieu à une perte d'enzyme de la partie ventrale ainsi que de la partie dorsale de la moitié caudale du noyau. On suggère que cela indique une organization somatotopique de la projection rubro-spinale chez le rat.

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Supported by a grant from the Canadian Medical Research Council.