Atropine-sensitive gastric excitation by stimulation of thoracic dorsal roots--antidromic activation of afferents?

In chloralosed cats, usually with ligated adrenals and paralysed with gallamine, the thoracic dorsal roots were electrically stimulated and gastric motor responses were recorded. Thoracic dorsal root stimulation regularly elicited gastric contractions after pretreatment with guanethidine and/or hexamethonium which were readily blocked by atropine. It was established that these gastric motor responses were due to peripheral stimulation of the dorsal root and not to spread to the ventral roots. Together with other results (Delbro & Lisander 1980) the findings suggest an antidromic activation of thin afferent fibres with excitatory collaterals to intramural cholinergic neurons which convey the gastric contractions.