[The reaction of the nonapeptidergic neurosecretory cells of the hypothalamic accessory groups to cold and immobilization stresses in rats].

Male Wistar rats were subjected to stresses of two different kinds: cooling (2 h at 4 degrees C) or immobilization (20 min). In the rat hypothalamus, oxytocinergic (OTE) and vasopressinergic (VPE) cells were studied immunohistochemically (PAP-method) in following magnocellular accessory groups: circular (CG), perifornical (PFG), ventrolateral (VLG), dorsolateral (DLG), extrahypothalamic (EHG), and periventricularly localized OTE cells (PVC). In cooled rats, sizes of cellular nucleoli increased significantly in both OTE and VPE cells of the CG, EHG and PVC indicating activation of hormone production. The immobilization stress caused the reverse changes of morphometric characteristics in the groups. Signs of VPE cell activation were revealed after both cooling and immobilization in the PFG only. The cells of VLG and DLG did not change significantly under both stresses. It is concluded that the accessory groups of nonapeptidergic cells in the hypothalamus are functionally different and each of them is of particular significance in the organism. The role of the accessory groups for peripheral endocrine gland regulation is discussed.