Pubertal changes in the medio-basal hypothalamic area after neonatal suprachiasmatic nucleus lesions in the rat

Summary In order to get more insight into the mechanism by which the onset of puberty is controlled, a developmental study on the displacement of catalase- and dopamine-containing cells in the hypothalamic region was done in rats which received a neonatal lesion of the suprachiasmatic nucleus. The displacement of cells is delayed after these lesions. However, the time lost at the beginning of the displacement is made up at the end of the migration.     

Pubertal changes in the medio-basal hypothalamic area after neonatal suprachiasmatic nucleus lesions in the rat

In order to get more insight into the mechanism by which the onset of puberty is controlled, a developmental study on the displacement of catalase- and dopamine-containing cells in the hypothalamic region was done in rats which received a neonatal lesion of the suprachiasmatic nucleus. The displacement of cells is delayed after these lesions. However, the time lost at the beginning of the displacement is made up at the end of the migration.     

Regularly firing neurones in the rat suprachiasmatic nucleus

Summary The spontaneous discharge of some suprachiasmatic neurones in vivo and in vitro was found to exhibit a very constant interspike interval. In vivo these cells were comparatively rare and appeared to be mutually coupled. These findings are discussed in relation to coupled oscillator theories of circadian rhythm generation.     

Regularly firing neurones in the rat suprachiasmatic nucleus

The spontaneous discharge of some suprachiasmatic neurones in vivo and in vitro was found to exhibit a very constant interspike interval. In vivo these cells were comparatively rare and appeared to be mutually coupled. The findings are discussed in relation to coupled oscillator theories of circadian rhythm generation.     

Bilateral lesions of suprachiasmatic nucleus eliminate circadian rhythms of oxygen consumption and the respiratory quotient in rats

Summary Bilateral lesions of the suprachiasmatic nucleus of the hypothalamus of rats abolished circadian rhythms of oxygen consumption and of the respiratory quotient (RQ). The RQ remained constant at a level intermediate between the maximum (about 1.0) and minimum (about 0.9) values in control animals.     

Bilateral lesions of suprachiasmatic nucleus eliminate circadian rhythms of oxygen consumption and the respiratory quotient in rats

Bilateral lesions of the suprachiasmatic nucleus of the hypothalamus of rats abolished circadian rhythms of oxygen consumption and of the respiratory quotient (RQ). The RQ remained constant at a level intermediate between the maximum (about 1.0) and minimum (about 0.9) values in control animals.     

Seasonal changes in the nitrate-reducing activity of a green alga

Zusammenfassung Trotz konstanter Kultur- und Versuchsbedingungen zeigt die Nitratreduktion intakter Zellen und zellfreier Extrakte der GrünalgeAnkistrodesmus braunii ausgeprägte jahresperiodische Schwankungen. Das Aktivitätsmaximum liegt in den Monaten Juni/Juli, das Minimum im Oktober/November.

---

---

This work was supported by the Deutsche Forschungsgemeinschaft.     

Seasonal variations in the fertilizing capacity ofBufo arenarum (Amphibia Anura) spermatozoa

Resumen La capacidad fecundante de los espermatozoides deBufo arenarum decae más rápidamente en verano que en invierno. Ello probablemente sea debido a la presencia, durante el invierno, de factores testiculares de protección.

---

---

This work was supported by a grant from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina and by the Population Council grant No. 71.68 awarded to the Consejo Nacional de Investigaciones Cientificas y Técnicas to be administered by the Instituto de Biología, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán.

---

The author is most grateful to Dr.F. D. Barbieri for his kind discussion and helpful advice in the course of the present study.     

Seasonal changes in the circadian variation of oral temperature during wakefulness.

The circadian change of oral temperature in 26 subjects was compiled for December, March and June. Average peak time delays up to 70 min, and a reduced daytime temperature rise were found in June compared with December.     

Seasonal changes in the lipids of the liver of the frog,Rana tigrina

Zusammenfassung Zu verschiedenen Jahreszeiten wurden Unterschiede im Lipoidgehalt der Froschleber festgestellt.     

Seasonal changes of circadian rhythms of human birth in northern Finland

Zusammenfassung Die Verteilung der Geburten im finnischen Lappland auf die Tagesstunden zeigt eine jahreszeitliche Schwankung der Phasenlage in der Geburtenrhythmik. Zur Mittwinterzeit fallen die meisten Geburten in die Zeit von 08.00 bis 20.00 Uhr, während sie in den anderen Jahreszeiten auf die Nacht und den Vormittag fallen.

---

---

Supported by a grant from the National Research Council for Sciences (Finland).     

Chlorpromazine causes vesicle population changes in the monoaminergic synapse of the rat caudate nucleus

Summary The population of monoaminergic synaptic vesicles in the rat caudate nucleus remained unchanged or slightly decreased 3 h after chlorpromazine (CP) administration, and clearly increased after 24 h. The diameter of synaptic vesicles became smaller when the vesicles increased. These findings suggest that CP causes presynaptic blocking in part of its actions and leads to a condition in which neural transmission is inactive. In the control animals, population of the vesicles tended to fluctuate following the circadian rhythm.     

Volume changes in the cell nuclei of the ventromedial nucleus of the rabbit following hemorrhage

Zusammenfassung Der Einfluss der starken Blutentnahme auf die Grösse der Zellkerne im Nucleus ventromedialis (VMN) wurde am Kaninchenhypothalamus untersucht und mit der Kerngrösse im Nc. ceruleus und im cerebellaren Cortex verglichen. Es wurde festgestellt, dass die morphologischen Veränderungen im VMN in drei Phasen verlaufen: 1. schnelle Kernverkleinerung, 2. Plateauphase und 3. Kernvergrösserung. Als Kontrollen wurden Tiere mit implantierten Carotiskanülen ohne Blutentnahme verwendet.     

Seasonal monoamine changes in the central nervous system ofMytilus edulis (Bivalvia)

Summary The levels of serotonin, dopamine and norepinephrine exhibit seasonal changes in the central nervous system of Mytilus edulis. These monoamines were higher during the summer and lower during the winter.     

Starvation-induced changes in the autoradiographic localisation of valine uptake by rat small intestine

We report here the effects of a 72-h fast on the localisation of Na-dependent [3H]-valine uptake by rat small intestine. Starvation results in the earlier appearance of valine transport during cell migration and an enhanced accumulation of the amino acid at the villus tip.     

Starvation-induced changes in the autoradiographic localisation of valine uptake by rat small intestine

Summary We report here the effects of a 72-h fast on the localisation of Na-dependent [³H]-valine uptake by rat small intestine. Starvation results in the earlier appearance of valine transport during cell migration and an enhanced accumulation of the amino acid at the villus tip.Acknowledgments. We wish to thank MW Smith, PS James and IS King (AFRC Institute of Animal Physiology, Babraham, Cambridge) for facilities and advice regarding autoradiography. Financial support from the British Digestive Foundation and Eli Lilly and Company is appreciated.