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F González-Aguilar

Publications and source records attributed to F González-Aguilar.

6 recordsLinked to original sources
PubMed2000

Electrical and chemical synaptic transmission as an interacting system.

It is proposed that presynaptic potassium efflux triggered by the nerve impulse may generate either excitatory or inhibitory responses depending on the neurotransmitter which more or less steadily impregnates the postsynaptic membrane. The jelly intersynaptic matrix may potentiate the efficiency of inoic intersynaptic signals. The synaptic vesicles are proposed to shuttle mitochondrial ATP towards the presynaptic membrane, thereby supplying the energy necessary to restore the membrane polarity after synaptic transmission. Plain structural data and currently accepted functional antecedents appear to justify the proposal.

Animals↗
PubMed1993

What do the synaptic vesicles contain?

The intersynaptic membranes of the rat brain cortex were found to remain firmly attached to one another after perfusion of strongly anisotonic solutions. Brains perfused with depolarizing and excitotoxic agents showed abundant, apparent intermingling of mitochondria and synaptic vesicles. The results suggest (i) that the intersynaptic membranes are not separated from one another by an essentially fluid intersynaptic medium as it is commonly assumed, but rather firmly attached to one another by a layer of faintly osmiophilic yet remarkably stable, water-insoluble material; and (ii) that the synaptic vesicles may be involved in adenosine triphosphate carriage. Well established multidisciplinary data are presented which appear to be in line with both possibilities.

2,4-Dinitrophenol↗
PubMed1989

Alignment and intracytoplasmic disintegration of synaptic vesicles in the brain cortex.

Perfusion fixation with highly concentrated aldehydes suggests that the synaptic vesicles undergo disintegration within the presynaptic ending upon touching the presynaptic membrane rather than being released by exocytosis into the intersynaptic cleft. Three factors have been explored in order to inquire further into the possible significance of the findings: (a) fixative concentration; (b) physiological activity; (c) cell depolarization. The transformation of the vesicles into amorphous, electron-dense material was observed in all experiments in all synapses, including those fixed with the lowest concentration of aldehydes. Besides, after acute ischemia and perfusion of excitatory and depolarizing pharmacological agents, the synaptic vesicles were seen to conflue upon the intersynaptic cleft in well-aligned rows. It was also found that the vesicles flow post mortem towards the intersynaptic cleft with absolute specificity.

Aldehydes↗
PubMed1988

Synaptic vesicle relationships with the presynaptic membrane as shown by a new method of fast chemical fixation.

Brief vascular perfusion of the rat brain with a mixture of concentrated aldehydes completely insolubilized the brain protein in less than 30 s and yielded excellent ultrastructural preservation. Abundant synaptic vesicles closely and specifically attached to the presynaptic membrane were constantly detected. These vesicles appeared to undergo progressive transformation into amorphous, electron-dense material. No evidence of vesicle exocytosis was detected in the brains perfused in vivo but fixations performed 1 h after death showed abundant exocytotic-like images. The results suggest that the vesicles may not be exocytotically released to the intersynaptic cleft but disintegrate intracytoplasmically in the immediate vicinity of the presynaptic membrane.

Animals↗