Zinc-positive presynaptic boutons of the rabbit hippocampus during early postnatal development

Abstract The evolution of vesicular zinc-containing boutons in the developing rabbit hippocampus has been studied during early postnatal life using the selenite–Danscher histochemical method. By P3, large immature mossy fiber boutons with labeled synaptic vesicles were seen in the hilus of the dentate gyrus and in the stratum lucidum of the CA3–CA4 hippocampal areas. After P5, smaller boutons with labeled vesicles were identified in the stratum oriens and stratum radiatum of all hippocampal areas, and even transiently in the stratum lacunosum of P6 animals. Vesicular zinc-containing boutons increased in number and underwent ultrastructural maturation; light microscope densitometric–volumetr…