Distribution and morphology of vasopressin‐, neurophysin II‐, and oxytocin‐immunoreactive cell bodies in the forebrain of the cat

Abstract

Experiments were done to provide a detailed map of the location and a description of morphological characteristics of vasopressin (AVP-IR)-, neurophysin II (NII-IR)- and oxytocin (OXY-IR)-immunoreactive neuronal perikarya in the forebrain of the cat. In addition, the location of cells in the forebrain retrogradely labeled following injections of tracers into the neurohypophysis was determined. The distribution of AVP-IR and NII-IR was similar in all cases studied. Most of the cells containing AVP-IR and OXY-IR were observed in the hypothalamic paraventricular (PVH) and supraoptic (SON) nuclei. In addition, AVP-IR and OXY-IR cell bodies were found in the regions of the nucleus of the diagonal band of Broca, the dorsal chiasmatic nucleus, the anterior hypothalamic-preoptic area, the periventricular area, the nucleus circularis, the perifornical area of the lateral hypothalamus, the accessory SON, the area of the tuber cinereum (Tca), and the medial nucleus of the amygdala. The density of AVP-IR cells was greater than that of OXY-IR cells in these regions. Several forebrain areas were also observed to contain only AVP-IR perikarya: the suprachiasmatic nucleus (Sc), the bed nucleus of the stria terminalis, and the region of the substantia innominata and ventral globus pallidus (SI/GP). In addition, the dorsomedial nucleus of the hypothalamus only contained OXY-IR perikarya. Most of the cells immunoreactive to AVP were multipolar and had spinelike processes over their somata and proximal dendrites. In addition, the majority of cells in the PVH and SON were round or oval, whereas those outside these nuclei were fusiform or triangular. The mean somal area of AVP-IR cells in the region of the SI/GP was significantly (P less than 0.05) larger than that of AVP-IR cells in all other regions examined, whereas the mean somal area of Sc AVP-IR cells was significantly (P less than 0.05) smaller than that of all other groups of AVP-IR cells examined. Most OXY-IR cells were similar morphologically to those immunoreactive to AVP, except that OXY-IR cell bodies and their appendages did not have spinelike processes. In addition, OXY-IR perikarya were generally of uniform size. OXY-IR cells in the PVH and accessory SON were significantly (P less than 0.05) larger than AVP-IR cells in the same regions, but were not different from AVP-IR cells in the lateral hypothalamus and SON.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunohistochemical Localization of Corticotropin-Releasing Factor, (Arginine8)-Vasopressin and Oxytocin Neurons in the Goat Hypothalamus.

“…This is in agreement with the observations in rats [27]. In contrast, in rabbits [16], guinea pigs [21] and cats [5], AVPand OXY-IR cells are concentrated in the lateral part and in the medial part of the nucleus, respectively. In monkeys [11], AVP-IR cells are distributed more ventrally and medially than OXY-IR cells.…”

“…The overall distribution pattern of these neuropeptides were generally consistent with those reported previously in other mammals [5,11,12,22,24,29]. The majority of CRF-IR cells were found in the parvocellular part of the PVN, and those of AVP-and OXY-IR cell bodies in the magnocellular parts of the PVN and SON, from which fibers were projected massively to the ME.…”

“…As to the SON, the majority of AVP-IR cells were found in the ventral part of the SON, as previously reported in cats [5,14]. On the other hand, OXY-IR cells mostly occurred in the dorsal part of the SON.…”

“…On the other hand, OXY-IR cells mostly occurred in the dorsal part of the SON. As in cats [5] and rabbits [16], AVP-IR cells were mainly located in the rostral part of the SON while OXY-IR cells in the caudal part.…”

“…In addition to CRF, recent studies have revealed that AVP and OXY can also stimulate ACTH secretion in rats [1,2,9,23,24]. These two neuropeptides are similarly distributed in the hypothalamo-pituitary system in some species [5,11,12,14,19,22,28,29]. Most of neurosecretory AVP and OXY cells are concentrated in the magnocellular part of the PVN and supraoptic nucleus (SON), and the fibers of these neuropeptides are observed in the ME.…”