Distribution of axons showing neurophysin-like immunoreactivity in cortical and anterior basal forebrain sites

The distribution of fibres reacting with neurophysin antisera has been studied in the frontal cortex and anterior basal forebrain of young and adult rats. Fibres reacting with antisera raised against neurophysin A (vasopressin-neurophysin) were observed in the medial bank of frontal cortex, the anterior hippocampal rudiment, the rostral extension of substantia innominata lying between nucleus accumbens and olfactory tubercle, bed nucleus of stria terminalis, ventral pallidum, substantia innominata, lateral preoptic and magnocellular preoptic area. Axons were also identified lying in the anterior tip of the lateral ventricle and amongst the cells of the proliferative subependymal layer lining the ventricle. The significance of these findings is discussed. Particular attention is paid to the known connections of these, and associated regions, with limbic dopaminergic cell groups.