title: Intestinal dysmotility and enteric neurochemical changes in a Parkinson's disease rat model.
abstract: Gastrointestinal disorders, constipation in particular, are the most common non-motor dysfunctions affecting Parkinson's disease (PD) patients. We have previously reported that rats bearing unilateral nigrostriatal lesion caused by 6-hydroxydopamine (6-OHDA) stereotaxic injection develop severe constipation together with a region-specific decrease of neuronal nitric oxide synthase (nNOS) in enteric neurons of the lower intestinal tract. Here, we extend these observations on other enteric neuronal subpopulations, investigating also the propulsive activity of isolated colonic specimens. Four weeks post 6-OHDA injection, lesioned rats showed a significant increase of vasoactive intestinal polypeptide (VIP) concomitant with the reduced expression of nNOS in the myenteric plexus of distal ileum and proximal colon; in particular VIP increased in a subpopulation of neurons actively expressing nNOS. On the other hand, choline acetyltransferase (ChAT) was not modified in any of the intestinal segments analyzed. Interestingly, we found a reduced expression of dopamine receptor type 2 (D2R) in proximal (-66.8%) and distal (-54.5%) colon, together with reduced peristalsis efficiency (decrease in intraluminal pressure and frequency of peristaltic events) in the 6-OHDA-lesioned rats. The selective depletion of dopaminergic nigrostriatal neurons is associated with changes in the expression of enteric inhibitory neurotransmitters, as well as of the D2R in intestinal specific regions. Moreover, 6-OHDA-lesioned rats demonstrated altered colon propulsive activity referable to the D2R decrease. Our findings unveil subtle mechanisms underlying the enteric neurochemical plasticity events evoked by disruption of the normal brain-gut cross-talk, giving a peculiar point of view on the pathophysiology of the severe constipation that frequently affects PD patients.
authors.affiliation: Department of Legal Medicine, Forensic Sciences and Pharmaco-Toxicology, University of Pavia, Pavia, Italy. mario.colucci1@gmail.com
authors.forename: Mario
authors.initials: M
authors.lastname: Colucci
authors.forename: Marila
authors.initials: M
authors.lastname: Cervio
authors.forename: Marisa
authors.initials: M
authors.lastname: Faniglione
authors.forename: Stefano
authors.initials: S
authors.lastname: De Angelis
authors.forename: Massimo
authors.initials: M
authors.lastname: Pajoro
authors.forename: Giovanna
authors.initials: G
authors.lastname: Levandis
authors.forename: Cristina
authors.initials: C
authors.lastname: Tassorelli
authors.forename: Fabio
authors.initials: F
authors.lastname: Blandini
authors.forename: Fausto
authors.initials: F
authors.lastname: Feletti
authors.forename: Roberto
authors.initials: R
authors.lastname: De Giorgio
authors.forename: Antonio
authors.initials: A
authors.lastname: Dellabianca
authors.forename: Stefano
authors.initials: S
authors.lastname: Tonini
authors.forename: Marcello
authors.initials: M
authors.lastname: Tonini
mesh_terms: D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003106:Colon / Q000201:enzymology / Q000503:physiopathology*; D004195:Disease Models, Animal; D017615:Enteric Nervous System / Q000201:enzymology / Q000503:physiopathology*; D005769:Gastrointestinal Motility; D007082:Ileum / Q000201:enzymology / Q000503:physiopathology; D007421:Intestine, Small / Q000201:enzymology / Q000503:physiopathology; D008297:Male; D009474:Neurons / Q000502:physiology; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D010300:Parkinson Disease / Q000201:enzymology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D052248:Nitric Oxide Synthase Type I; D002795:Choline O-Acetyltransferase