Why Can’t Rodents Vomit? A Comparative Behavioral, Anatomical, and Physiological Study

摘要: The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats mice appear to lack this response. It unclear whether these rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or key neural circuits. Moreover, it unknown are representative Rodentia with regards reflex. Here we conducted behavioral testing members all three major groups Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine copper sulfate (ig), failed produce either retching species (although other effects, e.g., locomotion, were noted). These also had constraints, which could limit the efficiency should be attempted, reduced muscularity diaphragm stomach geometry that well structured for moving contents towards esophagus compared can (cat, ferret, musk shrew). Lastly, an situ brainstem preparation was used make sensitive measures mouth, esophagus, shoulder muscular movements, phrenic nerve activity–key features episodes. Laboratory display any common coordinated actions indices after typical stimulation (resiniferatoxin vagal afferent stimulation) shrews. Overall results suggest inability general property absent neurological component most likely cause. implications findings utility as models area emesis research discussed.