Neuropeptide Y administered into cerebral ventricles stimulates sucrose ingestion in the near-term ovine fetus

OBJECTIVE: In adults, nutrient intake is controlled by opposing actions of appetite stimulants (eg, neuropeptide Y [NPY]) and suppressors (eg, leptin). Because NPY may exert a preferential role in mediating adult carbohydrate intake, we sought to determine the effect of central NPY on near-term fetal carbohydrate ingestion. STUDY DESIGN: Five pregnant ewes and fetuses were prepared with fetal vascular, sublingual, and intracerebroventricular catheters, electrocorticogram, and esophageal electromyogram electrodes and studied at 131 +/- 2 days' gestation. After a 2-hour baseline period, 10% sucrose was infused sublingually for the duration of the study. At 4 hours' time, NPY was injected into the fetal cerebral ventricles and fetal swallowing monitored for an additional 6 hours. RESULTS: During the basal period, mean (+/-SEM) swallowing averaged 0.8 +/- 0.1 swallows per minute. Fetal swallowing increased significantly in response to sublingual sucrose (1.3 +/- 0.1 swallows/min, P = .001), and further significantly increased at 4 to 6 hours after NPY injection into the cerebral ventricles (1.8 +/- 0.3, P = .001). CONCLUSION: These results indicate central NPY stimulation of fetal ingestion beyond that resulting from sublingual 10% sucrose. The in utero development of NPY-induced ingestive behavior may be in preparation for high neonatal caloric intake.