TY - JOUR

T1 - Wiring prior to firing: the evolutionary rise of electrical and chemical modes of synaptic transmission.

AU - Ovsepian, S.V.

AU - Vesselkin, N.P.

PY - 2014

Y1 - 2014

N2 - Paracrine signaling and coupling via intercellular conduits are widely utilized for cell-cell interactions from primitive eukaryotes to advanced metazoa. Here, we review the functional and molecular data suggestive of a phylogenic continuum between these primeval forms of communication with the chemical and electrical synaptic transmission of neurons. We discuss selective evidence for the essential role played by the shift of function in early cellular morphologies and protosynaptic scaffolds, with their co-optation for new functionality, which ultimately lead to the rise of the chemical synapse. It is proposed that, rather than representing a transitional element, mixed electrochemical synapses exemplify an exaptive effect. The nonadaptive model of the synaptic origin described herein supports the pluralistic hypothesis of evolutionary change.

AB - Paracrine signaling and coupling via intercellular conduits are widely utilized for cell-cell interactions from primitive eukaryotes to advanced metazoa. Here, we review the functional and molecular data suggestive of a phylogenic continuum between these primeval forms of communication with the chemical and electrical synaptic transmission of neurons. We discuss selective evidence for the essential role played by the shift of function in early cellular morphologies and protosynaptic scaffolds, with their co-optation for new functionality, which ultimately lead to the rise of the chemical synapse. It is proposed that, rather than representing a transitional element, mixed electrochemical synapses exemplify an exaptive effect. The nonadaptive model of the synaptic origin described herein supports the pluralistic hypothesis of evolutionary change.

KW - chemical synapse

KW - exaptation

KW - gap junction

KW - metazoan

KW - paracrine signaling

KW - synaptic evolution

U2 - 10.1515/revneuro-2014-0037

DO - 10.1515/revneuro-2014-0037

M3 - Article

VL - 25

SP - 821

EP - 832

JO - Reviews in the Neurosciences

JF - Reviews in the Neurosciences

SN - 0334-1763

IS - 6

ER -