Schlegel, Jerry F.

Resting pressure and deglutitive changes of pressure in the gastroesophageal sphincter of 12 healthy subjects were recorded as a tiny balloon-covered pressure transducer and open-tipped tubes connected to transducers were withdrawn through the sphincter by 0.5-cm stages. The pressures—both resting and deglutitive—detected by the balloon unit were of greater magnitude than those recorded by the open-tipped tubes. A reduction in pressure indicating relaxation was the outstanding deglutitive pressure change recorded in the subhiatal portion of the sphincter. In the segment of the sphincter at the hiatus, the subsequent contraction was as prominent as the relaxation. As the units traversed the suprahiatal portion of the sphincteric zone, the reduction of pressure (relaxation) became progressively less and the rise of pressure (contraction) with deglutition became greater. Contraction alone occurred at the points farthest orad. Measurements of time intervals from the start of swallowing in the pharynx indicated a caudad peristaltic progression of both relaxation and contraction through the gastroesophageal sphincteric zone. Submitted on December 21, 1959

This study was undertaken to define the motor activity of the fundus of the stomach. Observations were made on six healthy dogs with vagally innervated mucosal septal pouches of the fundus of the stomach and four other healthy dogs with identical pouches of the corpus of the stomach. In each dog the motor actions of the esophagus, gastroesophageal sphincter, gastric pouch, and gastric antrum were recorded simultaneously. The commonest motor activity recorded from the pouches of the fundus was a slow, phasic change in pressure or tone designated as a type III wave. Tiny pressure changes occurring at a rate of 5/min and identical to type I waves seen elsewhere in the stomach were sometimes recorded. Large "fundic" waves, occurring, when they were rhythmic, at a rate of about 3/min were occasionally seen on the records. Relaxation of the pouch of the fundus occurred after the majority of swallows, confirming the observation of other investigators that receptive relaxation of the fundus is an important component of the response to deglutition.

The pressure in the esophagus and its sphincters in seven well-trained, intact, healthy dogs was studied using three small water-filled polyethylene tubes attached to pressure transducers. To obtain resting pressures these tubes were withdrawn at intervals of 0.5–2.0 cm through the gastroesophageal junction, the esophagus and the pharyngoesophageal junction. Swallowing was induced by injection of water into the mouth or pharynx of the animals, and responses were recorded from selected sites. At rest, bands of elevated pressure about 2 cm wide were detected at the pharyngoesophageal and gastroesophageal junctions. The mean maximal pressures in the two zones were 20 and 6.9 cm of water, respectively. Pressure in the esophagus at rest was less than that in the gastric fundus. When swallowing began, the elevated pressure in the junctional zones decreased promptly, rose to high values as the peristaltic wave of deglutition swept into them, and then declined to resting levels. A peristaltic wave of high pressure swept through the esophagus with each swallow. These findings indicate that the junctional zones act as sphincters. Their behavior is identical to that in healthy human beings. The pressure pattern in the esophagus itself with swallowing is also the same in the two species, but in the dog the peristaltic wave moves faster and the rise of pressure is briefer. These differences may reflect the fact that the muscle of the dog's esophagus is entirely skeletal.

The response of the intra-arterial pressure to the cold immersion stimulus was studied in 42 healthy young adults, continuous direct (arterial-pressure) recording being used. The average systolic elevation was 22.6 mm. Hg and the average diastolic elevation was 16.3 mm. Hg. The difference between direct and indirect methods of measuring blood pressure was studied in 351 simultaneous determinations in 35 of these young adults. The direct systolic pressure averaged 9.7 mm. Hg higher and the diastolic pressure was 7.3 mm. Hg lower than the indirect measurement.