Correlation between Peptide YY-Induced Myoelectric Activity and Transit of Small-Intestinal Contents in Rats

Abstract

The effect of peptide YY (PYY) on the myoelectric activity of the small intestine was studied in relation to the transit of a 51Cr marker solution in fasted conscious rats. The myoelectric activity was recorded by means of bipolar electrodes implanted at 5, 20, and 35 cm from the pylorus. The marker was administered in the duodenum immediately after an activity front of a migrating myoelectric complex (MMC) had passed the first recording site. Under control conditions, the propagation of one activity front over the three recording levels was accompanied by the propulsion of 90.2 +/- 11.4% of the total radioactivity as one portion distal to the third electrode site. The median peak of the radioactivity was recovered at a distance approximately twice that propagated by an activity front. Intravenous infusion of PYY (50 pmol X kg-1 X min-1) had no effect on the occurrence of the MMC in the duodenum but interrupted its distal propagation and almost totally abolished the spiking activity in the jejunum. In comparison with controls, the transport of the marker was significantly retarded, and the median peak of the radioactivity was recovered proximal to the third electrode site. The results indicate that the small-intestinal contents are propelled as one portion in front of a propagating activity front. The inhibition of the activity front by PYY may account for the delay in the transit of the small-intestinal contents.(ABSTRACT TRUNCATED AT 250 WORDS)

The Chinese herbal preparation Qing Yi Tang (QYT) improves intestinal myoelectrical activity and Increases intestinal transit during acute pancreatitis in Rodents

“…Smooth muscular activity in response to slow wave activity propagates throughout the smooth muscular syncytium and is the first step of coupling mechanisms resulting in contractile activity (Lu et al, 1997;Storr et al, 2004). Thus, there is a important and close relationship between myoelectric activity and intestinal transit (al Saffar et al, 1985;Hellstrom et al, 1997). The impaired myoelectrical spikes observed in this study most likely reflect the disordered GI motility in the early stage of SAP in rats comparable to reports in acute necrotizing pancreatitis (ANP) (Leveau et al, 1996).…”

Colonic Mucin Discharge by a Cholinergic Agonist, Prostaglandins, and Peptide YY in the Isolated Vascularly Perfused Rat Colon

“…The present study shows for the first time that PYY induced the dis charge of mucus through cavitation of the apical granule mass. PYY is an endocrine peptide that is found primari ly in mucosal endocrine L cells of ileum, colon, and rec tum [9][10][11][12], The gastrointestinal effects of PYY include reduced gastric and pancreatic secretion [25][26][27], delayed gastric emptying [28,29], slowing of small-bowel transit [30], and an increase in intestinal absorption of water and electrolytes [31,32], In our study, a significant effect on mucus discharge was observed only when supraphysiological concentrations of PYY were administered. Although a hormonal action of PYY may be ruled out, the possibili ty that PYY exerted an effect on mucus secretion through a local/paracrine pathway cannot be excluded, since intmunohistochemical studies revealed that PYY cells some times had long cytoplasmic processes extending from the basal portion to the neighboring epithelial cells [9].…”

Impact of Gastric Bypass Surgery on Gut Hormones and Glucose Homeostasis in Type 2 Diabetes

“…In analogy with other GI peptides involved in regulating food intake, PYY also inhibits fasting small bowel motility (72) and gastric emptying (73). In rodents, PYY (3-36) does not influence glucose metabolism in the fasted state but increases glucose disposal during the hyperinsulinemic clamp.…”