Nucleus circularis and lateral preoptic regulation of osmotic thirst

Abstract

Small bilateral lesions of the nucleus circularis in rats produced a deficit in osmotic thirst, whereas subjects with similar-sized lesions of the lateral preoptic hypothalamus were almost identical to sham-operated rats in response to an osmotic challenge. Therefore, osmosensitive cells probably are more concentrated in the area of the nucleus circularis than in the lateral preoptic area. However, moderate-sized lesions in the lateral preoptic area resulted in a deficit in osmotic thirst, particularly when the damage was posterior to the anterior commissure. This research suggested that osmosensitive cells are diffusely represented in the preoptic area but become more concentrated in the anterior hypothalamus. This conclusion raised questions about the functional importance of the preoptic for osmoregulation and pointed to a more critical role for the nucleus circularis. To explain the increased water retention and increased antidiuretic hormone release following injections of hypertonic saline into the blood supply of the diencephalon, Verney (1947) suggested that osmoreceptors existed in the vascular bed of supraoptic nucleus of the hypothalamus. These osmoreceptors were proposed by Verney to be located in the supraoptic and paraventricular nuclei, which both produced antidiuretic hormone. Later evidence suggested that hypothalamic osmoreceptors existed in the lateral preoptic, medial preoptic, anterior, and lateral nuclei (

The bovine anterior hypothalamus: Characterization of the vasopressin–oxytocin containing nucleus and changes in relation to sexual differentiation

“…The nucleus circularis (NC; also called accessory supraoptic nucleus in the rat in Bodian and Maren () was clearly present in the pig, disambiguating it from the VON (van Eerdenburg & Swaab, ). It is also present in rats (Price Peterson, ), hamsters (Ferris, Axelson, Martin, & Roberge, ), cats (Caverson et al, ), dogs (Laqueur, ), and was recently reported in the human hypothalamus (Møller et al, ) and has been linked to osmotic functions in rats (Wallace & Harrell, ) and flank marking in hamsters (Ferris et al, ). We were not able to detect any NC in the bovine hypothalamus.…”

Modulation of social behavior by distinct vasopressin sources

“…The nucleus circularis (NC) is a small cluster of cells that contain AVP located within the anterior hypothalamus between the SON and PVN and has been historically implicated in osmotic thirst ( 180 , 181 ). The discovery that AVP release within the anterior hypothalamus (AH) drives social communication (i.e., flank marking) in male hamsters ( 182 ) and that non-selective NC lesions reduces flank marking, led to the suggestion that these cells could be one of the AVP sources important for flank marking ( 179 ).…”