Comparison of the effects of different isomers of bicuculline infused in the preoptic area on male rat sexual behavior

Intracerebral infusion of (+) bicuculline methiodide, but not of its (-) isomer, in the preoptic area, stimulated masculine sexual behavior in rat as evidenced by a decrease in the number of intromissions preceding ejaculation and a shortening of the ejaculation latency and postejaculatory interval. Data suggest a role of the GABAergic system in mediating masculine sexual behavior.     

Effects of selective dopamine D1 and D2 antagonists on male rat sexual behavior

Summary The effects of selective dopamine (DA) D₁ and D₂ antagonists on male rat sexual behavior were investigated. The D₁ antagonist (+)SCH-23390, 25–100 g kg^–1 s.c. –20 min, and the D₂ antagonist raclopride, 0.1–1.6 mg kg^–1 s.c., –20 min, decreased both the number of mounts and intromissions preceding ejaculation. No statistically significant effects in the time up to ejaculation or in the time up to the first intromission were noted, whereas both compounds produced a statistically significant increase in the post-ejaculatory interval. The effect can generally be characterized as psychomotor inhibition, and no evidence was obtained for a specific role of DA D₁ or D₂ receptors in the mediation of male rat sexual behavior.The expert technical assistance of Ms Elisabeth Wallin is gratefully acknowledged. The figures were skilfully prepared by Ms Madelene Kröning at the Department of Psychology. This study received support from the Bank of Sweden tercentenary Foundation, The Swedish MRC and Wilhelm and Martina Lundgren Foundation.     

Effects of selective dopamine D1 and D2 antagonists on male rat sexual behavior

The effects of selective dopamine (DA) D1 and D2 antagonists on male rat sexual behavior were investigated. The D1 antagonist (+)SCH-23390, 25-100 micrograms kg-1 s.c. -20 min, and the D2 antagonist raclopride, 0.1-1.6 mg kg-1 s.c., -20 min, decreased both the number of mounts and intromissions preceding ejaculation. No statistically significant effects in the time up to ejaculation or in the time up to the first intromission were noted, whereas both compounds produced a statistically significant increase in the post-ejaculatory interval. The effect can generally be characterized as psychomotor inhibition, and no evidence was obtained for a specific role of DA D1 or D2 receptors in the mediation of male rat sexual behavior.     

Is feminine differentiation of the brain hormonally determined?

Summary The androgen insensitive, genetically male rat pseudohermaphrodite displays neither masculine or feminine sexual behavior when primed with the appropriate sex hormones. although in the absence of androgen imprinting the animal develops anatomically as female, our results suggest that feminine differentiation of the brain requires active imprinting by perinatal hormone(s), possibly adrenal progesterone.The research was partially supported by a grant from the Rockefeller Foundation.A. S. Goldman is a U.S.P.H.S. Career Development Awardee (No. HD-13,628).     

Activation with (±)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

Summary I.p. (±)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

Activation with (+/-)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

I.p. (+/-)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

Effects of cadmium on the immune system of mice

Summary Chronic oral exposure of mice to Cd⁺⁺ inhibits cell-mediated immunity of delayed type hypersensitivity induced by sheep red blood cells (SRBC). No effect was detected on humoral immune response to SRBC. Spleen cells derived from mice exposed to Cd⁺⁺ showed in vitro enhanced response to T and B cell mitogens. These results demonstrate that Cd⁺⁺ exposure alters the immune system of mice.Dedicated to Prof. Georg Henneberg on the occasion of his 70th anniversary on 12.10.1978.Acknowledgments. Supported by a grant from the Umweltbundesamt. We thank Ms Odenwald, Ms Schulz, Klinikum Steglitz, and Ms Emeis, Robert Koch-Institut Abt. Immunologie, for the excellent technical assistance.     

FITC-dextrans as fluorescence and electron microscopic tracers in studies on capillary and cell permeability of the CNS

Summary FITC-dextrans can be detected at the ultrastructural level as round electron dense particles, with no sign of distortion or aggregation. Because this tracer is a stable, non-toxic polymer of biological origin obtainable in a wide range of molecular weights, it may be useful for further studies of tissue permeability.The author is grateful to Ms. H. Büscher and Ms. S. Klemt, Department of Pathology, for their excellent technical assistance.     

Plakorin,a potent Ca2+-ATPase activator from the Okinawan marine spongePlakortis sp.

Summary A new cyclic peroxide, plakorin, which is a potent sarcoplasmic reticulum (SR) Ca^a+-ATPase activator has been isolated from the Okinawan marine spongePlakortis sp., its structure was elucidated on the basis of spectral data.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance.     

Smallest zinc quantities affect the histamine release from peritoneal mast cells of the rat

Summary Seven individual 0.025-mg doses of zinc administered as lactose tablets on consecutive days, significantly increase histamine release from peritoneal mast cells of the rat. Seven individual doses of 0.25 g cause a somewhat smaller, though still very pronounced increase in the release in comparison with zero control.Acknowledgments. We thank Ms T. L. Pham and Ms K. Löppen for their technical assistance.     

Symbioramide,a novel Ca2+-ATPase activator from the cultured dinoflagellateSymbiodinium sp.

Summary A novel sphingosine derivative, symbioramide, has been isolated from the laboratory-cultured dinoflagellateSymbiodinium sp. as a sarcoplasmic reticulum (SR) Ca²⁺-ATPase activator, and its structure elucidated to be1 on the basis of spectral and chemical means.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance.     

Captopril (SQ 14,225): In vitro and in vivo influence on the proliferative response of rat lymphocytes

Summary Captopril in vitro (50–500 g/ml) increased³H-TdR incorporation in unstimulated and mitogen-stimulated cultures of rat lymphocytes. Unseparated spleen and lymph node cells of rats orally treated with captopril (50 mg/kg/day×4) showed decreased basal and mitogen stimulated³H-TdR incorporation. The removal of macrophages abrogated this inhibitory effect. Leucine aminopeptidase activity of macrophages was reduced — in vivo and in vitro — by captopril.Acknowledgments. The authors thank the Squibb Institute for Medical Research for the gift of Captopril. The excellent technical assistance of Ms B. Hasselriis, Ms B. Rumler and Ms E. Greve Petersen is gratefully acknowledged.     

Genes regulating the appearance of two kinds of fruit inMicroseris strain B87 (Asteraceae:Compositae)

Summary The annual hybrid strainMicroseris B87 (M. pygmaea x M. bigelovii) produces 2 kinds of fruit (achenes) on its flowering heads, outer hairy and inner smooth ones. 2 unlinked genes are identified that determine the relative number of hairy achenes, on a logarithmic scale.Supported by grants Ba 536/1-6 from the Deutsche Forschungsgemeinschaft, and DEB-780940 from the National Science Foundation.We thank Ms. E. Oeldorf and particularly Ms. A. König for technical assistance.     

Peritoneal macrophages from adjuvant arthritic rats enhance tumour cell growth in vitro

Summary Peritoneal macrophages from rats with adjuvant arthritis enhance the incorporation of³H-thymidine in 2 tumour cell lines in vitro. Maximal enhancement is found during the development of the secondary lesions, and it is suggested that the immunologic commitment of the macrophages could interfere with their regulation of tumour cell proliferation in vivo.Acknowledgments. The authors thank Drs P.F. Engel and M.P. Andreasen from the Finsen Institute, Copenhagen, for their gift of tumour cells and Ms E. Greve Petersen, Ms B. Hasselriis and Ms F. Norris for excellent technical assistance.     

Electro-mechanical noise in atrial muscle fibres of the carp

Summary Steady membrane voltage fluctuations have been observed in atrial muscle fibres of the carp. These voltage fluctuations produce minute mechanical oscillations, as revealed by an interference contrast microscope. The steady voltage fluctuations may be related to abnormal automaticity in the heart.Supported by the U.S. Israel Binational Science Foundation, Jerusalem, and is part of a thesis to be submitted by Ms Akselrod to the Tel-Aviv University. We thank Ms M. Bendikowski for her efficient technical assistance.     

Lipoperoxidation rates and drug-oxidizing enzyme activities in the liver and placenta of some mammal species during the perinatal period

Summary Lipoperoxidation and drug-metabolizing enzymes were measured in livers and placentas of different mammal species during the perinatal period. In placentas and fetal livers of rat, rabbit and guinea-pig, cofactor-supported lipoperoxidation was negligible, as were the activities of drug-oxidizing enzymes. Human fetal liver contained an intact drug-oxidizing electron transport chain, and lipoperoxidation activity was accordingly observed. It is suggested that lesions mediated by lipoperoxidation may be possible in human fetus, but they are less probable in animal fetuses.The skillful technical assistance of Ms.Liisa Tuhkanen and Ms.Vuokko Väisänen is gratefully acknowledged.     

Antifertility activity of trimethylphosphate in male rats

Summary The toxic effect of trimethylphosphate on rat testes was investigated after oral dosing with 250 mg/kg for either 5 days/week for 30 days or 6 days/week for 60 days. After these prolonged treatments azoospermia resulted.Acknowledgments. The authors wish to thank Ms M. Michelles, Ms A. Murray and Ms R. Peake for their technical support.     

A simple system for mechanical and electrical recordings from frog nerve-muscle preparation

Summary A device is described which can be used for simultaneous measurement of the muscle action potential and the contraction of the frog gastrocnemius nerve-muscle preparation. The apparatus is characterized by ease of construction, good accuracy and reliability.We thank Ms.C. Friedemann for preparation of the drawings; Ms.A. Middelmann for technical assistance.     

α-Adrenoceptor blocking action of hymenin,a novel marine alkaloid

Summary In the rabbit isolated aorta, hymenin (10^–6 M) a novel marine alkaloid, caused a parallel rightward shift of the dose-response curve for norepinephrine without affecting that for histamine or KCl, suggesting that hymenin is a competitive antagonist of -adrenoceptors in vascular smooth muscles.Acknowledgments. We thank Ms A. Kajiwara and Ms M. Hamashima of this institute for their technical assistance, and Prof. Y. Hirata of Meijo University for his encouragement.     

AnAnolis skin melanophore assay suitable for photoaffinity labeling studies with α-MSH

Summary Visual determination of MSH-induced pigment migration in melanophores of small pieces ofAnolis carolinensis skin is standardized by first measuring photoelectrometrically the change in reflection/transmission of the whole dorsal skin in response to different hormone concentrations. This method allows the rapid and precise recording of time-response curves after photoaffinity labeling of MSH receptors or of dose-response curves of large series of synthetic compounds.Acknowledgments. We wish to thank Ms V. Jäggin, Ms C. Schulthess and Ms G. van Hees for excellent technical assistance, Dr. R. Andreatta, Ciba-Geigy AG, Basel, for his generous gift of -MSH and Prof. A Pletscher for his continuous interest. This work was supported by the Swiss National Science Foundation.