Although at rest, the rat esophagus is tensed anisotropically in situ

Abstract

A cephalic organ, the rat lacrimal gland, is tensed in situ (Lorber, Adv Exp Med Biol 438:75–80, 1998), might a cervical one also be extended? After trachea removal under pentobarbital, 7 fasted male rats, wt 359 ± 10g (mean ± sd), had two dots placed axially in the mid‐esophagus about 5 mm apart to indicate length alterations. Width measurements were made at the level of the rostral dot. A calipers put in the jaws of a digital micrometer was used. For each dimension values were gotten at baseline, after removal of dorsal CT with small vessels, and after freeing by transections just beyond both dots. Overall statistical analysis was by the F test, and for paired values by the Tukey test. P ≤ 0.05 was deemed significant. Resting length between the dots was 4,80 ± 0.76 mm. After CT removal, 4.77 ± 0.78 mm. After transections to free the esophagus, 3.42 ± 0.97 mm. F≤0.001. This length was less than both baseline, P ≤0.01, and CT removal, P ≤0.001. Baseline width was 3.04 ± 0.39 mm. After CT removal, 3.09 ± 0.37 mm. After freeing, 3.28 ± 0.37 mm. F≤ 0.01. This width value exceeded both baseline, P ≤ 0.01, and CT removal, P 0.05, values. The esophagus shortens and widens as its attachments are removed. So, it is anisotropically tensed in situ. If it were not tensed the values would not have changed. The width change is likely secondary to the shortening, keeping its volume unchanged. Personal support.