Horseradish peroxidase study in rat of the neural connections of the organum vasculosum of the lamina terminalis.

Using highly localized injections by a transbuccal approach a study of the afferent and efferent connections of the organum vasculosum laminae terminalis (OVLT) with horseradish peroxidase (HRP) methods was carried out. The results showed that the OVLT has direct connections to several hypothalamic nuclei (anterior, preoptic, lateral preoptic, ventromedial nucleus) and to extrahypothalamic (central gray, locus coeruleus, subfornical organ) regions. There was not a direct projection from the supraoptic nucleus. Some of these connections may be involved in the functional actions of the OVLT observed after central injections of angiotensin II.