Presynaptic modulation by somatostatin in the neostriatum.
Medium spiny projection neurons (MSNs) are the main neuronal population in the neostriatum. MSNs are inhibitory and GABAergic. MSNs connect with other MSNs via local axon collaterals that produce lateral inhibition, which is thought to select cell assemblies for motor action. MSNs also receive inhibitory inputs from GABAergic local interneurons. This work shows, through the use of the paired pulse protocol, that somatostatin (SST) acts presynaptically to regulate GABA release from the terminals interconnecting MSNs. This SST action is reversible and not mediated through the release of dopamine. It is blocked by the SST receptor (SSTR) antagonist ciclosomatostatin (cicloSST). In contrast, SST does not regulate inhibition coming from interneurons. Because, SST is released by a class of local interneuron, it is concluded that this neuron helps to regulate the selection of motor acts.
Lopez-Huerta
Violeta Gisselle
VG
Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, PO Box 70-253, Mexico City, DF, 04510, Mexico.
Tecuapetla
Fatuel
F
Guzman
Jaime N
JN
Bargas
Jose
J
Galarraga
Elvira
E
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000378:metabolism; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003342:Corpus Striatum / Q000166:cytology / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000378:metabolism; D018691:Excitatory Amino Acid Antagonists / Q000378:metabolism; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology*; D016202:N-Methylaspartate / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000378:metabolism*; D014633:Valine / Q000031:analogs & derivatives / Q000378:metabolism; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000378:metabolism
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D013004:Somatostatin; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; C056639:2-amino-5-phosphopentanoic acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D014633:Valine