Figure 3.
Schematic illustration of neurons in the PVN projecting to the median eminence. Recurrent axon collaterals can be seen contacting neighboring parvocellular neurons. (A) The inset shows recurrent terminals in which both the nerve terminal and postsynaptic dendrite are immunoreactive for the same peptide (★) and non-recurrent synaptic contacts where the nerve terminal and postsynaptic dendrite are not immunoreactive for the same neuropeptide (⧫) Electron micrographs illustrating the two types of presynaptic terminals. The presynaptic terminal shown in (B) is immunoreactive for vasopressin, as indicated by the electron dense DAB staining of the vesicles. The terminal shown in (C) is not immunoreactive for vasopressin. Scale bar 500 nm.