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The coexistence of multiple receptors in a single nerve terminal provides evidence for pre‐synaptic integration
Author(s) -
Ladera Carolina,
Godino María del Carmen,
Martín Ricardo,
Luján Rafael,
Shigemoto Ryuichi,
Ciruela Francisco,
Torres Magdalena,
SánchezPrieto José
Publication year - 2007
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2007.04964.x
Subject(s) - neurotransmission , metabotropic receptor , neuroscience , metabotropic glutamate receptor , class c gpcr , glutamate receptor , receptor , microbiology and biotechnology , excitatory postsynaptic potential , inhibitory postsynaptic potential , chemistry , long term depression , biology , ampa receptor , biochemistry
Abstract Excitatory synaptic transmission is inhibited by G protein coupled receptors, including the adenosine A 1 , GABA B , and metabotropic glutamate receptor 7. These receptors are present in nerve terminals where they reduce the release of glutamate through activating signaling pathways negatively coupled to Ca 2+ channels and adenylyl cyclase. However, it is not clear whether these receptors operate in distinct subpopulations of nerve terminals or if they are co‐expressed in the same nerve terminals, despite the functional consequences that such distributions may have on synaptic transmission. Applying Ca 2+ imaging and immunocytochemistry, we show that these three G protein coupled receptors coexist in a subpopulation of cerebrocortical nerve terminals. The three receptors share an intracellular signaling pathway through which their inhibitory responses are integrated and coactivation of these receptors produced an integrated response. Indeed, this response was highly variable, from a synergistic response at subthreshold agonist concentrations to an occluded response at high agonist concentrations. The presence of multiple receptors in a nerve terminal could be responsible for the physiological effects of neurotransmitter spillover from neighboring synapses or alternatively, the co‐release of transmitters by the same nerve terminal.