The accessory magnocellular neurosecretory system of the rostral human hypothalamus.

The morphology and neurophysin expression of the magnocellular accessory neuroendocrine system located in the rostral human hypothalamus is investigated in a series of brains obtained at autopsy. The hypothalami were fixed in formalin and embedded in paraffin, or after cryoprotection, frozen for cryostat sectioning. Paraffin sections were either stained with Luxol Fast blue or immunoreacted for neurophysin I or neurophysin II, the precursor molecule for oxytocin and vasopressin. Further, 50-µm-thick serial cryostat sections were immunoreacted with the same antibodies. Both the paraventricular and supraoptic nuclei as well as the hypothalamo-hypophysial tracts exhibited strong immunoreactivity for the neurophysin antibodies. In addition, large collections of immunoreactive accessory magnocellular nuclei and single scattered neurophysin-positive neurons were located in the preoptic region between the paraventricular and supraoptic nucleus among the hypothalamo-hypophysial nerve fibers. In addition, smaller collections of neurophysin-immunoreactive neurons were located in the basal part of this region. Among the accessory magnocellular nuclei, the classical circular nucleus was identified. Accessory magnocellular neurons were often located along the blood vessels and projections of some of these neurons penetrated the vascular endothelium. The accessory magnocellular cell bodies expressed either neurophysin I or neurophysin II immunoreactivity. Summarizing, the accessory magnocellular system in the human brain is large and differs in morphology compared to the system seen in other vertebrates. The neurons of this system contain both vasopressin and oxytocin. Some neurons of the accessory neuronal systems might secrete vasopressin or oxytocin directly into the blood stream.

Expression of vasopressin mRNA in the hypothalamus of individuals with a diagnosis of schizophrenia.

OBJECTIVE: This study investigates the expression of mRNA encoding vasopressin in the hypothalamus of autopsy brains of individuals diagnosed with schizophrenia. METHODS: Ten brains of individuals with schizophrenia and 10 brains from individuals without any disease were examined during autopsy. The hypothalamic block was dissected and immersion fixed in paraformaldehyde, sucrose substituted, frozen, and cut into 20-µm-thick coronal cryostat sections. The sections were hybridized with an S-35-labeled DNA antisense oligo probe and after washing covered by an X-ray film. The hybridization signals on the films were transferred to a computer and densitometrically quantified. RESULTS: The densitometry signals showed a statistically significant lower mRNA expression (53% decrease; p = 0.014) in the paraventricular nucleus of the individuals with schizophrenia compared to the controls. In the supraoptic nucleus, the decrease in the group with schizophrenia was 39% compared to the controls, but this decrease was not statistically significant (p = 0.194). CONCLUSIONS: Our results show a low expression of mRNA encoding vasopressin in the paraventricular nucleus of the individuals with schizophrenia. We suggest that vasopressin is not directly involved in the pathogenesis of schizophrenia, but might influence schizophrenic symptoms via vasopressin receptors located in the social behavioral neural network in the forebrain.