Effect of maturation of the magnitude of mechanosensitive and chemosensitive reflexes in the premature human esophagus.
OBJECTIVE
To investigate the effect of esophageal mechanosensitive and chemosensitive stimulation on the magnitude and recruitment of peristaltic reflexes and upper esophageal sphincter (UES)-contractile reflex in premature infants.


METHODS
Esophageal manometry and provocation testing were performed in the same 18 neonates at 33 and 36 weeks postmenstrual age (PMA). Mechanoreceptor and chemoreceptor stimulation were performed using graded volumes of air, water, and apple juice (pH 3.7), respectively. The frequency and magnitude of the resulting esophago-deglutition response (EDR) or secondary peristalsis (SP), and esophago-UES-contractile reflex (EUCR) were quantified.


RESULTS
Threshold volumes to evoke EDR, SP, or EUCR were similar. The recruitment and magnitude of SP and EUCR increased with volume increments of air and water in either study (P < .05). However, apple juice infusions resulted in increased recruitment of EDR in the 33 weeks group (P < .05), and SP in the 36 weeks group (P < .05). The magnitude of EUCR was also volume responsive (all media, P < .05), and significant differences between media were noted (P < .05). At maximal stimulation (1 mL, all media), sensory-motor characteristics of peristaltic and EUCR reflexes were different (P < .05) between media and groups.


CONCLUSIONS
Mechano- and chemosensitive stimuli evoke volume-dependent specific peristaltic and UES reflexes at 33 and 36 weeks PMA. The recruitment and magnitude of these reflexes are dependent on the physicochemical properties of the stimuli in healthy premature infants.
Jadcherla
Sudarshan Rao
SR
Sections of Neonatology and Pediatric Gastroenterology and Nutrition at the Columbus Children's Hospital, Department of Pediatrics, the Ohio State University School of Medicine and Public Health, Columbus, Ohio, USA. jadcherlas@pediatrics.ohio-state.edu
Hoffmann
Raymond G
RG
Shaker
Reza
R
D000388:Air; D001628:Beverages; D002628:Chemoreceptor Cells / Q000502:physiology*; D003679:Deglutition / Q000502:physiology; D004947:Esophagus / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D008365:Manometry; D008465:Mechanoreceptors / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D010477:Perfusion; D010528:Peristalsis / Q000502:physiology; D011999:Recruitment, Neurophysiological; D012018:Reflex / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D014867:Water
D014867:Water