title: Behavioural learning-induced increase in spontaneous GABAA-dependent synaptic activity in rat striatal cholinergic interneurons.
abstract: Cholinergic striatal interneurons play a crucial role in cognitive aspects of context-dependent motor behaviours. They are considered to correspond to the tonically active neurons (TANs) of the primate striatum, which phasically decrease their discharge at the presentation of reward-related sensory stimuli. The origin of this response is still poorly understood. Therefore, in the present paper, we have investigated whether synaptic changes establish in cholinergic interneurons from young rats that have learned a rewarded, externally cued sensorimotor task. Corticostriatal slices were prepared from both control and trained rats. No significant change in intrinsic membrane properties and evoked synaptic activity was observed in cholinergic interneurons, nor the responsiveness to exogenously applied dopaminergic and glutamatergic agonists was modified. Conversely, an increased occurrence of spontaneous bicuculline-sensitive depolarizing postsynaptic potentials (sDPSP) was recorded. The frequency of the GABAA-mediated sDPSP was increased in comparison to not-conditioned rats. Overall, these results suggest that after learning a rewarded sensorimotor paradigm an increased GABA influence develops on cholinergic interneurons. The origin of this effect might be searched in collaterals of GABAergic output spiny neurons as well as in GABAergic striatal interneurons impinging onto cholinergic interneurons. This intrastriatal mechanism might be involved in the phasic suppression of discharge of TANs at the presentation of reward-related sensory stimuli.
authors.affiliation: Fondazione Santa Lucia IRCCS, Rome and Department of Neuroscience, Neurological Clinic, University 'Tor Vergata', Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Bonsi
authors.forename: Tiziana
authors.initials: T
authors.lastname: Florio
authors.forename: Annamaria
authors.initials: A
authors.lastname: Capozzo
authors.forename: Antonio
authors.initials: A
authors.lastname: Pisani
authors.forename: Paolo
authors.initials: P
authors.lastname: Calabresi
authors.forename: Alberto
authors.initials: A
authors.lastname: Siracusano
authors.forename: Eugenio
authors.initials: E
authors.lastname: Scarnati
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003342:Corpus Striatum / Q000502:physiology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D007395:Interneurons / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D009068:Movement; D009433:Neural Inhibition; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000502:physiology*; D012201:Reward; D009435:Synaptic Transmission
chemical_list: D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D011963:Receptors, GABA-A; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000109:Acetylcholine; D001640:Bicuculline