Sensitivity of the developing chick myocardium to the positive inotropic effects of calcium and isoproterenol

Summary The present results show that the sensitivity of the chick myocardium to the positive motropic effect of Ca⁺⁺ decreases during development and that the Ca⁺⁺ concentration of the physiological solution used must be lowered below normal to study the effects of positive inotropic agents in preparations from younger embryos. Isoproterenol elicits positive inotropic responses in 7–9-day embryonic ventricle and in newborn chick atria; however, the 4-day embryonic myocardium is unresponsive to isoproterenol.This work was supported by Grant No. HL-15995 from the National Heart Institute (USPHS).The authors would like to thank Dr.F. E. Shideman for the isolated tissue baths used in these experiments.     

The metabolism of the male antifertility agent 1-amino-3-chloropropan-2-ol in the rat

Summary The male antifertility agent 1-amino-3-chloropropan-2-ol (ACP,I) has been shown to be metabolized to-chlorohydrin (III) and metabolites of-chlorohydrin. This accounts for the similar antifertility and renal toxicity effects of both compounds.     

A cannabinoid with cardiovascular activity but no overt behavioral effects

Summary Abnormal-⁸-tetrahydrocannabidiol (ABN-⁸-THC) failed to elicit central nervous system and cardiovascular effects in laboratory animals. Abnormal-cannabidiol (ABN-CBD) was also devoid of overt behavioral effects but produced marked hypotension with only slight bradycardia in anesthesized dogs.Acknowledgment. This work was supported by NIDA (grant No. DA-00574-01 and DA-00490) and Virginia Heart Society (grant No. RR-05697)     

A centrally induced vasodepressor response after intravenous administration of whole venom ofNaja mossambica pallida in cats

Summary Naja mossambica pallida venom administered i.v. (300 /kg) produces an initial brief fall in blood pressure, due to a direct myocardial depressant effect, and a sustained fall due to central depressant effect.This study was supported by University of Nairobi research grants (670–376). We also thank Mr E. Njogu for photographic assistance.     

A new one-step synthesis of hexahydrocannabinoid analogs

Summary A one-step synthesis of hexahydrocannabinoid analogs (HHC) is described making use of the condensation of phenolic ketones and aldehydes with citronellal in the presence of pyridine.Grateful thanks are accorded to Drs L. Chopard and S. Selvavinayakam for spectral measurements and Dr I. Fleming for useful discussion.R. Mechoulam and Y. Gaoni, Recent advances in the chemistry of Hashish, in: Progress in the Chemistry of Organic natural products, vol. 25, p. 175. Ed. L. Zechmeister. Springer Verlag, Wien 1967; R. Mechoulam, Marijuana Chemistry and Pharmacology, metabolism and clinical effects. Academic Press, New York 1973; R. Mechoulam, N. K. McCallum and S. Burstein, Chem. Rev.76, 75 (1976).     

Starfish saponins. Part 101. Further 24-O-glycosidated steroids from the starfishHacelia attenuata

Summary On the basis of comparative spectral data, the structures of 3 novel steroidal glycosides from the Mediterranean starfishHacelia attenuata have been elucidated as3, 4 and5. These are further examples of a novel group of 24-O-glycosidated steroids recently encountered in the same species and in the Pacific speciesProtoreaster nodosus.Part 9. L. Minale, C. Pizza, R. Riccio and F. Zollo, Experientia39 (1983) 567. This contribution is part of the Progetto Finalizzato Chimica fine e secondaria del C.N.R., Roma.Acknowledgments. We thank Prof. K. Nakanishi, Columbia University, New York, for FD-mass spectral analyses, the Centro Interfacoltà di Metodologie Chimico-Fisiche for 270 MHz NMR facilities, and Miss R. Aquino for part of the experimental work.     

The activity of monoamine oxidases A and B in gamma-irradiated rabbit brains

Summary The activities of monoamine oxidases A and B towards 5-hydroxytryptamine and -phenethylamine, respectively, were compared in the left and right caudatus, hippocampus, parietal cortex, cerebellum and frontal cortex 6 months after gamma-irradiation (single dose of 23 Gy) of either the right hemisphere or of the whole rabbit brain (in which case, a dose of 16 Gy). No difference in monoamine oxidase A or B activities were found in any of the brain regions.Acknowledgment. This study was supported by grants from the Swedish Medical Research Council (12x–5664 and 04x–4145), Hansson's, Lion's, Mångberg's and Sundblad's funds.     

Metabolism of the snailCryptozona ligulata during regeneration of optic tentacles

Summary The biochemical changes in the hemolymph and tissues were followed during regeneration of the optic tentacles of the snailCryptozona ligulata (Pulmonata-Stylommatophora). There is a remarkable increase in total carbohydrates in hemolymph and tissues and glycogen in tissues at the expense of free amino acids and fatty acids. It is clear that ablation of the optic tentacles stimulates carbohydrate synthesis through glyconeogenic routes. The optic tentacles regenerate completely in 18–21 days.     

Identification of an acyclic diterpene alcohol in the defense secretion of soldiers ofReticulitermes lucifugus

Summary The defense secretion of soldiers ofReticulitermes lucifugus has been shown to contain, predominantly, (R)-(–)-(E,E)-geranyllinalool together with germacrene A and -farnesene.This report covers part of a collaborative study with J.-L. Clément, Lab. d'Evolution, Université P. et M. Curie, Paris, to whom we are grateful for supplies of material and discussions. We also thank Dr O.T. Jones for collections ofReticulitermes lucifugus.     

Birefringence signals and tension development in single frog muscle fibres at short stimulus intervals

Summary The early large birefringence signal and mechanical activity were studied together in isolated single fibres of frog skeletal muscle with double stimulation at short stimulus intervals (2–60 msec) at room temperature and at 4–6°C. In all fibres tested, extra tension and additional birefringence signal in response to the second stimulus appeared simultaneously and suddenly upon increasing the stimulus interval. The shape of the stimulus-interval versus tension-development curve makes it highly improbable that subthreshold calcium release occurs at shorter stimulus intervals; therefore, tension development reliably reflects Ca-release in these experiments. In contrast to the report by Suarez-Kurtz and Parker, birefringence signal and calcium release are shown not to be dissociated by double stimulation. This result supports the hypothesis that the early large birefringence signal is an intrinsic indicator of calcium release from the sr during EC-coupling in skeletal muscle.