Arterial chemoreceptor‐like activity in the abdominal vagus of the rat.

Abstract

Centripetal activity in fibers in the ventral abdominal vagus nerve of the rat was studied by recording from fine strands of the divided nerve within the abdomen. In the starved animal, few spontaneously active fibers were located. A proportion of these showed changes in activity in response to changes in F1, O2 which were typical of arterial chemoreceptor afferent nerves. The resting discharge in these preparations was 0.8-8.0 impulses/s. In response to extreme hypoxic hypoixa, histotoxic hypoxia or acetylcholine, this discharge increased markedly, with a maximum mean activity of up to 25 impulses/s. Both the mean SD ratio and statistical comparison with a noise equation were used to assess the apparent random nature of the spike intervals. The spike intervals were random but the latter test was inconclusive. This chemoreceptor-like activity may originate from the abdominal vagal paraganglia. These structures may be part of a more generally distributed chemoreceptor system.