Altered gastric tone and motility response to brainstem dopamine in a rat model of parkinsonism.

Altered gastric tone and motility response to brainstem dopamine in a rat model of parkinsonism. Am J Physiol Gastrointest Liver Physiol. 2019 May 01;: Authors: Bove C, Anselmi L, Travagli RA Abstract The majority of Parkinson's disease (PD) patients experience gastrointestinal (GI) dysfunction. Recently, we described a nigro-vagal pathway, which uses dopaminergic (DA) inputs to dorsal motor nucleus of the vagus (DMV) and A2 area neurons to modulate gastric motility and tone. This pathway is disrupted in a rodent model of PD. The aim of the present study was to test the hypothesis that brainstem dopaminergic modulation of gastric tone and motility is altered in a rodent model of PD. Male Sprague Dawley rats received 3 weekly intraperitoneal injections of 10mg/kg paraquat (PQ) or saline (control). In naive conditions, DA microinjection in the DMV induced a gastroinhibitory response in 100% of animals. In 19/28 of the paraquat-treated animals, however, microinjection of DA in the DVC induced a biphasic response with an initial increase in gastric tone and motility followed by a profound gastroinhibition. The excitatory response to DA microinjection was attenuated by a combination of DA1- and DA2-like receptor antagonists. Conversely, the inhibitory response was reduced by the DA2-like antagonist only. Pretreatment with the α2-adrenoceptor antagonist, yohimbine, did not modulate the response to DA, thus excluding the involvement of the...
Source: Am J Physiol Gastroi... - Category: Gastroenterology Authors: Tags: Am J Physiol Gastrointest Liver Physiol Source Type: research