Parasympathetic innervation of the rodent spleen?

摘要: Many workers in the field doubt that the rodent spleen receives parasympathetic innervation (1, 5, 7, 9), but some (2, 3), though not all (4), previous articles from this group argue that it does. The evidence in favor is based on finding labeled neurons in the dorsal motor nucleus of vagus (DMV) after injection into the spleen of either the transynaptic tracer pseudorabies virus (2) or the conventional retrogradely transported tracer Cholera toxin subunit B (3), which does not traverse synapses. At face value, the latter finding implies the presence of preganglionic vagal fibers (and thus, presumptively, also parasympathetic ganglion cells) within the spleen parenchyma. The alternative explanation is that labeling in DMV in these experiments was due to inadvertent spread of the tracer to vagal fibers located nearby. In this context, Fox and Powley (6) demonstrated the ease with which retrogradely transported tracers injected …