Contractile dysfunction and nitrergic dysregulation in small intestine of a primate model of Parkinson’s disease

The relationship between nigrostriatal tract TH-ir and contractile responses of the ileum. The effect of MPTP treatment on TH-ir in the substantia nigra (SN, a, b, e) and the caudate nucleus and putamen c, d, f and the effect of lesioning on agonist evoked and spontaneous contractile response of ileum. MPTP treatment resulted in marked reduction of TH-ir neurones e and TH-ir nerve terminals in the caudate nucleus and the putamen f. Agonist evoked and spontaneous contractile responses of the normal, drug naive ileum (open data points) and the ileum obtained from MPTP (shaded data points) treated common marmosets. Administration of carbachol g and histamine h evoked a concentration dependent contraction of the isolated ileum which were not significantly different between the normal ileum and those from MPTP treated animals. However, the frequency of spontaneous activity was significantly larger in preparations obtained from MPTP animals i while the amplitude of spontaneous contractions appeared lower j although this reduction did not reach statistical significance. Administration of noradrenaline (NA) or D1 ({"type":"entrez-nucleotide","attrs":{"text":"A77636","term_id":"6089301","term_text":"A77636"}}A77636) or D2 (ropinirole) agonists affected the frequency and the amplitude of the spontaneous contractions similarly. Panels k and l show correlation between the frequency of contraction (number of contraction/min) and motor disability k and the number of TH-ir neurones in the SN. Each bar is the mean？±？s.e.m. of n？=？7. *P？<？0.05; **P？<？0.001; ***P？<？0.000