Descending pathways with monosynaptic action on motoneurones

Zusammenfassung Motoneuronen, sowohl zu Streckwie Beugemuskeln, werden von absteigenden Bahnen des Rückenmarkes supraspinalen Ursprungs monosynaptisch beeinflusst. Es konnte gezeigt werden, dass die Wirkung an den Motoneuronen der Streckmuskeln aus dem Nucleus vestibularis lateralis (Deiters) stammt.     

Extrapyramidal pathways with monosynaptic effects upon primate α-motoneurons

, , , , , -.     

The effect of L-Dopa on the spinal monosynaptic mass reflex

Summary After i. v. injection of reserpine, the monosynaptic mass reflex (MSMR) is depressed in spinalized cats. However, the complete recovery of MSMR was obtained 30 min after L-Dopa application. Pimozide, a dopamine-receptor blocking agent, blocked this action of L-Dopa. It is presumed that dopaminergic receptors are involved in the action of L-Dopa on spinal MSMR.     

The action of a phenothiazine derivative on enzymes of the pentose phosphate pathway

Résumé La thiopérazine, qui est un derivé de la famille de la phénothiazine, a le pouvour d'inhibition sur l'activité du glucose-6-phosphate déhydrogénase et du 6-phosphogluconate déhydrogénase dans les globules rouges. Ce pouvoir est modifié si on ajoute du TPN dans le système enzymatique. Le degré de cette modification correspond à la dose de TPN employée.

---

---

Supported by the Nebraska Fund for Psychiatric Research.     

The effects of passive muscle stretching on the discharge of individual phrenic motoneurones

Conclusion From the results of the present experiments the following conclusion may be drawn: since phrenic motoneurones are activated by muscle stretching, it is possible that the involved muscle receptor afferents may influence the ventilatory control in muscular excercise.

---

Zusammenfassung An narkotisierten, gelähmten und mit Sauerstoff beatmeten Hunden konnte gezeigt werden, dass passive Muskeldehnung reflektorisch die Impulsfrequenz einzelner Motoneurone desN. phrenicus erhöht und zur Rekrutierung neuer Einheiten führt.

     

Local action of vitamin A on amphibian limb regeneration

Summary Axolotl forearms isolated from upper arm tissue either surgically or by local irradiation regenerate excessive structures after vitamin A treatment. This demonstration excludes the possibility of regeneration being altered by enhanced cellular migration and thus indicates that vitamin A respecifies cells close to the site of amputation.     

A contribution on the mode of action of D 860

Zusammenfassung Es wird auf die Unwirksamkeit von D 860 bei Ratten hingewiesen, bei denen 2 h vor Verabreichung von D 860 Hyperglykaemie durch parenterale Verfütterung von Glukose hervorgerufen wurde. Die Hypothese wird ausgesprochen, dass Hyperglykaemie einer der Faktoren sein könnte, die die Unwirksamkeit des Sulphonylharnstoffes bewirken.     

Integrative pattern of reflex actions by impulses in large muscle spindle afferents on motoneurones to hip muscles

Zusammenfassung Es werden die intrazellulären Potentiale an Motoneuronen von Hüftmuskeln abgeleitet. Motoneurone des HüftstreckersSemimembranosus werden von Ia-Impulsen der Hüftstrecker und Kniebeuger erregt, Motoneurone des HüftstreckersAdductor femoris dagegen von den Hüftstreckern und Kniestreckern. Motoneurone der Hüftbeuger werden von Ia-Impulsen gehemmt, nicht nur von deren Antagonisten, sondern auch vom KniestreckerVasto Cruralis.     

A metabolic pathway of gramine in barley

Résumé Nous avons observé que quand la gramine marqué au carbone attaché au noyau hétérocyclique a été administrée à des pousses d'orge agées de 60 jours (dans l'obscurité), 10% de la radioactivité a passé au CO₂ expiré et 0.4% au tryptophane.

---

---

This investigation was supported by a grant from the University Medical Research Fund for which one of us (G.A.D.) is grateful. We are grateful to Dr.C. I. Abou-Chaar for useful discussions.     

Hexobarbital action in rats with flavonoid-deficiency

Summary In flavonoid-deficient rats, hexobarbital-sleeping times are prolonged. The hexobarbital concentrations in brain, liver and plasma are increased. These results are discussed as a consequence of an impaired drug metabolism.     

Functional interaction between TRPC1 channel and connexin-43 protein: a novel pathway underlying S1P action on skeletal myogenesis

We recently demonstrated that skeletal muscle differentiation induced by sphingosine 1-phosphate (S1P) requires gap junctions and transient receptor potential canonical 1 (TRPC1) channels. Here, we searched for the signaling pathway linking the channel activity with Cx43 expression/function, investigating the involvement of the Ca²⁺-sensitive protease, m-calpain, and its targets in S1P-induced C2C12 myoblast differentiation. Gene silencing and pharmacological inhibition of TRPC1 significantly reduced Cx43 up-regulation and Cx43/cytoskeletal interaction elicited by S1P. TRPC1-dependent functions were also required for the transient increase of m-calpain activity/expression and the subsequent decrease of PKCα levels. Remarkably, Cx43 expression in S1P-treated myoblasts was reduced by m-calpain-siRNA and enhanced by pharmacological inhibition of classical PKCs, stressing the relevance for calpain/PKCα axis in Cx43 protein remodeling. The contribution of this pathway in myogenesis was also investigated. In conclusion, these findings provide novel mechanisms by which S1P regulates myoblast differentiation and offer interesting therapeutic options to improve skeletal muscle regeneration.     

A note on the mechanism of action of UV-irradiation of amphibian embryos

The actions on amphibian embryos of UV-irradiation, exposure to Li+ or exposure to ouabain show interesting parallels with their effects on spontaneous release at the presynaptic terminals of the neuromuscular junction. It is suggested that these treatments serve to raise intracellular Ca2+ ([Ca2+]i) in these examples, and that UV-promoted abnormalities in embryogenesis are a consequence of changes in [Ca2+]i at critical stages in development.     

A note on the mechanism of action of UV-irradiation of amphibian embryos

Summary The actions on amphibian embryos of UV-irradiation, exposure to Li⁺ or exposure to ouabain show interesting parallels with their effects on spontaneous release at the presynaptic terminals of the neuromuscular junction. It is suggested that these treatments serve to raise intracellular Ca²⁺ ([Ca²⁺ _i) in these examples, and that UV-promoted abnormalities in embryogenesis are a consequence of changes in [Ca²⁺]_i at critical stages in development.     

A promoting action of cyclic GMP on contractions of guinea-pig vas deferens

Summary The effect of dbc-GMP has been studied in ductus deferens of the guinea-pig. The nucleotide potentiated the contractions induced by electrical field stimulation and by adrenergic agonists. The site of action was probably in the smooth muscle cell, since the release of excitatory transmittor was not influenced.This work was supported by the Swedish State Medical Research Council (04X-4498).     

A new efferent pathway in the cockroach CNS

Riassunto Viene descritta una nuova via efferente della catena ganglionare diPeriplaneta americana, che origina nel 1° ganglio addominale, raggiunge i nervi cercali (NXI) ed è interrotta da sinapsi in ciascuno dei sei gangli addominali. Vengono riferiti la velocità di conduzione nei connettivi ed i tempi di trasmissione a livello dei gangli.