title: Cholinergic excitation from the pedunculopontine tegmental nucleus to the dentate nucleus in the rat.
abstract: In spite of the existence of pedunculopontine tegmental nucleus (PPTg) projections to cerebellar nuclei, their nature and functional role is unknown. These fibers may play a crucial role in postural control and may be involved in the beneficial effects induced by deep-brain stimulation (DBS) of brainstem structures in motor disorders. We investigated the effects of PPTg microstimulation on single-unit activity of dentate, fastigial and interpositus nuclei. The effects of PPTg stimulation were also studied in rats whose PPTg neurons were destroyed by ibotenic acid and subsequently subjected to iontophoretically applied cholinergic antagonists. The main response recorded in cerebellar nuclei was a short-latency (1.5-2 ms) and brief (13-15 ms) orthodromic activation. The dentate nucleus was the most responsive to PPTg stimulation. The destruction of PPTg cells reduced the occurrence of PPTg-evoked activation of dentate neurons, suggesting that the effect was due to stimulation of cell bodies and not due to fibers passing through or close to the PPTg. Application of cholinergic antagonists reduced or eliminated the PPTg-evoked response recorded in the dentate nucleus. The results show that excitation is exerted by the PPTg on the cerebellar nuclei, in particular on the dentate nucleus. Taken together with the reduction of nicotinamide adenine dinucleotide phosphate-diaphorase-positive neurons in lesioned animals, the iontophoretic experiments suggest that the activation of dentate neurons is due to cholinergic fibers. These data help to explain the effects of DBS of the PPTg on axial motor disabilities in neurodegenerative disorders.
authors.affiliation: Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio, Coppito 2, I-67100 L'Aquila, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Vitale
authors.affiliation: Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio, Coppito 2, I-67100 L'Aquila, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Mattei
authors.affiliation: Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio, Coppito 2, I-67100 L'Aquila, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Capozzo
authors.affiliation: Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio, Coppito 2, I-67100 L'Aquila, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Pietrantoni
authors.affiliation: ​ASL RM2 Regional Center for Functional Neurosurgery and DBS, Operative Unit of Stereotactic and Functional Neurosurgery, CTO Alesini Hospital, Via San Nemesio 21, 00145 Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Mazzone
authors.affiliation: Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio, Coppito 2, I-67100 L'Aquila, Italy. Electronic address: scarnati@univaq.it.
authors.forename: E
authors.initials: E
authors.lastname: Scarnati
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001703:Biophysics; D002529:Cerebellar Nuclei / Q000502:physiology*; D018678:Cholinergic Agents / Q000494:pharmacology; D002799:Cholinergic Fibers; D004558:Electric Stimulation; D007478:Iontophoresis; D008297:Male; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D045042:Pedunculopontine Tegmental Nucleus / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time
chemical_list: D018678:Cholinergic Agents; D009252:NADPH Dehydrogenase; D000109:Acetylcholine
keywords: acetylcholine; cerebellum; electrophysiology; neurodegenerative disorders; pedunculopontine tegmental nucleus