Porocytosis: A transient pore array secretes the neurotransmitter packet

Abstract

The porocytosis hypothesis is based on the arrayed nature of synaptic vesicles which forms the anatomical functional unit of secretion. The presynaptic array and the postsynaptic array of receptors form a synaptomere which is the unit of transmission. A transient increase in calcium ions, triggered by an action potential, activates all pores of the array to pulse transmitter. The array insures transmission while permitting a frequency dependent amount of secretion. Therefore the amount of secretion is variable which permits plasticity. Secretion from the array has the property of immediate synaptic plasticity whereas a change in array size would change synaptic strength. The robust nature of the array insures fidelity of transmission, a frequency dependent dynamic signature of transmission giving the property of immediate plasticity; and, a change in array size yields a change in synaptic strength for long term reliability.

Mouse Chromaffin Cells Have Two Populations of Dense Core Vesicles

“…In dopamine neurons, flickers in the fusion pore result in the partial release of vesicular dopamine (Staal et al 2004). The amount of secretion is variable in the porocytosis model as well (Kriebel et al 2005). Elhamdani et al (2001) recorded amperometric events while applying different patterns of electrical stimulation to chromaffin cells; they found that quantal size increased as a function of increased intracellular Ca 2ϩ .…”

Feynman’s Classification of Natural Phenomena and Physical Aspects of 2014 Nobel Prize in Physiology or Medicine

“…In this subsection, we will focus our attention on the electrical mechanism of intercellular interaction caused by the generation and propagation of AP along the axon. A discussion of some of the physicochemical aspects of the problem of cell-to-cell communication and synaptic transmission with regard for the porosytosis hypothesis and synaptomers having a Feynman's Classification of Natural Phenomena hexagonal geometry, as well as a quantative description of this problem based on nonlinear kinetic models can be found, for example, in [21][22][23][24].…”

“…In the inanimate (inorganic) world, they arise in Benard cells [10], in crystals and alloys with hexagonal or other type of symmetry [11], on the surface of the Salt Lake Uyuni in Bolivia [12], in geological colonnades Giant's Causeway in Ireland [13], in the cloud structure around Saturn's North Pole [14], in such carbon modifications as fullerene C 60 having 62.5% hexagonal faces (1986 Nobel Prize in Chemistry) [15] and graphene being a hexagonal monoatomac plane (2010 Nobel Prize in Physics) [16,17], etc. In the living (organic) world, hexagonal structures appear in grid cells of brain (2014 Nobel Prize in Physiology or Medicine) [18], in beeswax honeycombs [19], in such biomedical phenomena as the spreading depression of Leao and other neurological dysfunctions [20], in the problem of cell-to-cell communication (synaptic transmission) [21][22][23] with regard for the porosytosis hypothesis and hexagonal synaptomers [24], etc. The striking geometric similarity of these structures, as well as the variaty of objects in which they appear, suggests that there should probably exist a universal explanation or, in other words, the first principle underlying their formation.…”

Secretion: Essential transport at the plasma membrane

“…Silver brought the discussion to the level of mechanism applicable to both vesicular and constitutive secretion, considering the interactions among lipids and calcium ions: knitting the morphology, calcium imaging, electrophysiology, and physical chemistry of learning. Their papers (Kriebel et al, 2005; Silver and Pappas, 2005) that follow provide detailed discussions of porocytosis and their contributions to this exciting hypothesis.…”