Penetration of phospholipases A2 and C into the squid (Loligo pealii) giant axon

Summary Following 1 h exposure, the level of phospholipase A₂ penetration into the axoplasm of the squid giant axon was 107 to 350% of that in the external media; corresponding values for phospholipase C were 18 to 31%. Phospholipases can therefore be used to study phospholipid function in axons since they can penetrate through connective tissue and Schwann cell to reach the axolemma.I thank Dr.Toshio Narahashi for allowing me to use his laboratory facilities at the Marine Biological Laboratory, Woods Hole, Mass. for the dissection of squid axons. Expert technical assistance in these studies were provided by Mr.Steven Trudel and Mr.Stuart Owen Rosenberg. This work was supported in part by a grant from the University of Connecticut Research Foundation.     

Ineffectiveness of adrenocorticosteroids and adrenocorticotropin in altering Na−K currents in squid giant axon

Zusammenfassung Adrenocorticosteroide und Adrenocorticotropin bewirkten in hohen Konzentrationen keine Änderungen der Na–K Ströme in Tintenfischriesenaxon; das weist darauf hin, dass die Ionenbegebenheiten, die das Axenpotential hervorrufen, durch diese Hormone nicht beeinflusst sind.     

Penetration of phospholipases A2 and C into the squid (Loligo pealii) giant axon.

Following 1 h exposure, the level of phospholipase A2 penetration into the axoplasm of the squid giant axon was 107 to 350% of that in the external media; corresponding values for phospholipase C were 18 to 31%. Phospholipases can therefore be used to study phospholipid function in axons since they can penetrate through connective tissue and Schwann cell to reach the axolemma.     

Ineffectiveness of lysergic acid diethyl amide−25 (LSD) on altering Na-K currents in squid giant axon

Zusammenfassung Nachweis, dass Lysergsäurediäthyl-amid^–25 (LSD) die Ionenströme von Na und K im Riesen-axon des Tintenfisches auch in hohen Konzentrationen nicht beeinflusst.     

Ureteral pacemaker potentials recorded with the sucrose gap technique.

Ureteral contractions occur at intervals which are integral multiples of the period of pacemaker potentials recorded in vitro from the renal pelvis with a sucrose gap, suggesting that a gating mechanism in the pyeloureter regulates the rate at which the pacemaker initiates contractions.     

Model of the effect of 4-aminopyridine at the level of potassium channels of the giant axon of the squid, Logigo forbesi L.]

Most of the effects of 4-aminopyridine on the potassium conductance of the giant axon of the Squid can be explained in terms of a simple model based on the physicochemical properties of the molecule and what is known about the structure of the potassium "channels".     

Pentobarbital: Presynaptic effect in the squid giant synapse

Summary In concentrations that produced synaptic blockade in the squid giant synapse, sodium pentobarbital produced a dose-related, reversible decrease of the calcium spike of the presynaptic terminal.This work was performed while Dr Morgan was a Grass Foundation Fellow at the Marine Biological Laboratory, Woods Hole, Massachusetts, USA.The authors thank Dr J. Z. Yeh for the loan of the 4-aminopyridine and Dr G. H. Acheson for helpful suggestions.     

Neuron in the gracile nucleus with myelinated axon hillock

Zusammenfassung Die Ultrastruktur des unmyelinisierten Initialsegments des Ursprungskegels von Achsenzylindern ist bekannt. Im Gegensatz dazu wurde im Nucleus gracilis ein kleines Neuron gefunden, dessen Achsenzylinder kein unmyelinisiertes Initialsegment aufweist: die Myelinscheide beginnt schon auf dem Ursprungskegel und es wird auf die neurophysiologischen Gesichtspunkte, die sich aus diesen Fakten ergeben, hingewiesen.     

Histochemical detection of the position of metal microelectrode

Zusammenfassung Die Methode der histochemischen Detektion der Lage der Metallmikroelektrode wird beschrieben. Nachdem die Aktionpotentiale registriert worden sind, wird das Eisen aus der Mikroelektrode durch Elektrolyse ins Gewebe eingeführt, und anschliessend in Serienschnitten mit histochemischen Methoden nachgewiesen.     

Rhythmic wavelets recorded from an in vitro preparation of mammalian retina

Zusammenfassung Die rhythmischen Potentiale an der aufsteigenden Phase derb-Welle des von der In-vitro-Präparation der Warmblüternetzhaut abgeleiteten Elektroretinogramms wurden in vivo dargestellt.     

Intracellular pH of Limulus ventral photoreceptor measured with a double-barrelled pH microelectrode

Summary The intracellular pH of the Limulus ventral photoreceptor was measured with a double-barrelled pH microelectrode and found to be 7.01±0.04 SE (n=9).This work was supported by the Swiss National Science Foundation, grants Nos. 3.634.075 and 3.128.73.Acknowledgments. We thank Drs L. R. Pucacco and N. W. Carter for technical advice and a gift of pH glass. We also thank Drs M. Tsacopoulos and F. Baumann for helpful discussion.