Localization of cardiac parasympathetic preganglionic neurons in the medulla oblongata of pigeon, Columba livia: a study using fragment C of tetanus toxin.
The binding fragment of tetanus toxin, fragment C, was injected into several different regions of the pigeon heart. Retrogradely and/or transneuronally labeled cardiomotor parasympathetic preganglionic neurons were found in two separate nuclei within the medulla oblongata. The majority of fragment C-immunolabeled cells was confined to the caudal division of the nucleus ambiguus. This nuclear region is likely to be homologous to the ventrolateral nucleus of the external formation of the nucleus ambiguus in mammals. A smaller fraction (10-30%) of fragment C-positive cardiomotor preganglionic neurons were localized within a restricted portion of the ventrolateral subnucleus of the dorsal motor nucleus of the vagus nerve. This dual cardiac representation in an avian is very similar to the organization established in several mammalian species, and suggests that the brainstem organisation of cardiac parasympathetic efferents is evolutionarily stable across avians and mammals.
Cabot
J B
JB
Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794-5230.
Carroll
J
J
Bogan
N
N
D000818:Animals; D001370:Axonal Transport; D010856:Columbidae; D005726:Ganglia, Parasympathetic / Q000033:anatomy & histology* / Q000166:cytology; D006735:Horseradish Peroxidase; D008526:Medulla Oblongata / Q000033:anatomy & histology* / Q000166:cytology; D009474:Neurons / Q000166:cytology*; D013744:Tetanus Toxin
D013744:Tetanus Toxin; D006735:Horseradish Peroxidase