Fidel Ramón

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Studies of the interaction of anaesthetics with various preparations, from whole animals to organic solvents, have been continuing since Overton and Meyer found a correlation between anaesthetic potency and solubility in olive oil. Although the physiological basis of anaesthesia is far from clear, one popular hypothesis is that anaesthetics act primarily by(More)
We have developed a technique for cannulation and internal perfusion of crayfish segmented lateral axons. Experiments on perfused and non-perfused axons lead to the following conclusions: 1. Internally perfused segmented axons behave very similarly to non-perfused axons. 2. The axial electrical resistance of the junctional region is almost as low as a(More)
The chemokine IL-8 is known to be synthesized by glial cells in the brain. It has traditionally been shown to have an important role in neuroinflammation but recent evidence indicates that it may also be involved in rapid signaling in neurons. We investigated how IL-8 participates in rapid neuronal signaling by using a combination of whole-cell recording(More)
Described are studies of propagation of action potentials through inhomogenous axon regions through experiments performed on squid giant axons and by computer simulations. The initial speed of propagation of the action potential is dependent upon the stimulus waveform. For a rectangular pulse of current, the action potential travel initally at a high speed(More)
Clear evidence of sleep in invertebrates is still meager. Defined as a distinct state of reduced activity, arousability, attention, and initiative, it is well established in mammals, birds, reptiles, and teleosts. It is commonly defined by additional electroencephalographic criteria that are only well established in mammals and to some extent in birds.(More)
Electrical signs of neural activity correlated with stimuli or states include a subclass called event-related potentials. These overlap with, but can often be distinguished from, simple stimulus-bound evoked potentials by their greater dependence on endogenous (internal state) factors. Studied mainly in humans, where they are commonly associated with(More)
Gap junctions between crayfish lateral axons were studied by combining anatomical and electrophysiological measurements to determine structural changes associated during uncoupling by axoplasmic acidification. In basal conditions, the junctional resistance, Rj, was approximately 60-80 k omega and the synapses appeared as two adhering membranes; 18-20-nm(More)
In this paper we extend the simulation of the voltage clamp of a single nerve fiber to a bundle of axons. These simulations included not only the description of the voltage clamp circuit and a single unidimensional cable to represent the preparation in the "node" region of a double sucrose gap used previously but also a series resistance and a shunt(More)