Morphometric evaluation of neurophysin-immunoreactivity in the human brain: pronounced inter-individual variability...

The neurohypophyseal peptides vasopressin and oxytocin have a variety of well documented behavioural effects. Accordingly, terminals and receptors that respectively contain or bind these peptides have been identified throughout the central nervous system (CNS) in experimental animals. In this study we have mapped the distribution of neurophysin I and II-immunoreactive structures in the human CNS. Neurophysins are portions of the precursor proteins for vasopressin and oxytocin, and are found specifically in structures that contain these peptides. In addition, we have quantitatively compared neurophysin neurons and fibers in the brains of individuals with no history of neurologic or psychiatric abnormality, and in brains of patients dying with psychotic illness categorized as schizophrenia. These latter brains were collected prior to the advent of pharmacologic treatment and were available from the Vogt collection. Our findings show wide variations of morphometric values obtained for neurophysin-stained structures in different CNS regions in normal subjects, but provide evidence for abnormal values in certain brain areas in untreated schizophrenia, in the hypothalamic paraventricular nucleus, internal pallidal segment and substantia nigra. These findings suggest that the function of vasopressin and/or oxytocin may be disturbed in these brain regions in schizophrenia. Further investigation will be required to establish whether these differences contribute to, or are a consequence of the disease mechanism.