TY - JOUR
T1 - Coexpression of multiple metabotropic glutamate receptors in axon terminals of single suprachiasmatic nucleus neurons
AU - Chen, Gong
AU - Van Den Pol, Anthony N.
PY - 1998/10
Y1 - 1998/10
N2 - Glutamate is the primary excitatory transmitter in axons innervating the hypothalamic suprachiasmatic nucleus (SCN) and is responsible for light- induced phase shifts of circadian rhythms generated by the SCN. By using self-innervating single neuron cultures and patch-clamp electrophysiology, we studied metabotropic glutamate receptors (mGluRs) expressed by SCN neurons. The selective agonists for group I (3,5-dihydroxy-phenylglycine), group II ((S)-4-carboxy-3-hydroxyphenylglycine), and group III (L(+)-2-amino-4- phosphonobutyric acid) mGluRs all depressed the evoked IPSC in a subset (33%) of single autaptic neurons, suggesting a coexpression of all three groups of mGluRs in the same axon terminals of a single neuron other neurons showed a variety of combinations of mGluRs, including an expression of only one group of mGluR (18%) or coexpression of two groups of mGluRs (27%). Some neurons had no response to any of the three agonists (22%). The three mGluR agonists had no effect on postsynaptic γ-aminobutyric acid (GABA) receptor responses, indicating a presynaptic modulation of GABA release by mGluRs. We conclude that multiple mGluRs that act through different second messenger pathways are coexpressed in single axon terminals of SCN neurons where they modulate the release of GABA presynaptically, usually inhibiting release.
AB - Glutamate is the primary excitatory transmitter in axons innervating the hypothalamic suprachiasmatic nucleus (SCN) and is responsible for light- induced phase shifts of circadian rhythms generated by the SCN. By using self-innervating single neuron cultures and patch-clamp electrophysiology, we studied metabotropic glutamate receptors (mGluRs) expressed by SCN neurons. The selective agonists for group I (3,5-dihydroxy-phenylglycine), group II ((S)-4-carboxy-3-hydroxyphenylglycine), and group III (L(+)-2-amino-4- phosphonobutyric acid) mGluRs all depressed the evoked IPSC in a subset (33%) of single autaptic neurons, suggesting a coexpression of all three groups of mGluRs in the same axon terminals of a single neuron other neurons showed a variety of combinations of mGluRs, including an expression of only one group of mGluR (18%) or coexpression of two groups of mGluRs (27%). Some neurons had no response to any of the three agonists (22%). The three mGluR agonists had no effect on postsynaptic γ-aminobutyric acid (GABA) receptor responses, indicating a presynaptic modulation of GABA release by mGluRs. We conclude that multiple mGluRs that act through different second messenger pathways are coexpressed in single axon terminals of SCN neurons where they modulate the release of GABA presynaptically, usually inhibiting release.
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U2 - 10.1152/jn.1998.80.4.1932
DO - 10.1152/jn.1998.80.4.1932
M3 - Article
C2 - 9772250
AN - SCOPUS:0031739978
SN - 0022-3077
VL - 80
SP - 1932
EP - 1938
JO - Journal of neurophysiology
JF - Journal of neurophysiology
IS - 4
ER -