Immunohistochemical Distribution of Delta Sleep Inducing Peptide in the Rabbit Brain and Hypophysis

Abstract

The distribution of delta sleep inducing peptide (DSIP) in the rabbit brain has been studied with immunohistochemical techniques. DSIP-like immunoreactivity was predominantly detected in the basal forebrain, hypothalamus and hypophysis. Even in colchicine-pretreated animals, immunolabeled cell bodies were relatively few. They were mostly scattered through the ventrolateral septum, the diagonal band of Broca and preoptic areas. Clusters of positive cell bodies were also found in the arcuate nucleus and adjacent lateral hypothalamic areas. Large populations of varicose fibers and terminal-like structures were observed in the juxtaventricular zone of the ventrolateral septum, in the preoptic areas and lamina terminalis especially around the preoptic recess of the third ventricle and more caudally, in the ventromedial nucleus of the hypothalamus. Dense networks of immunolabeled fibers were visualized in the median eminence and pituitary stalk where many fibers could be seen in close apposition to the capillaries. Many DSIP-immunoreactive fibers were observed in the subfornical organ. Other extra-hypothalamic regions displaying a low-to-moderate density of immunoreactive fibers were the indusium griseum, the hippocampus, the fimbria of the fornix, the subcommissural organ, the medial habenula and, occasionally, the medial periaqueductal gray. Most cells of the pars intermedia and a few cells of the pars distalis of the anterior pituitary were DSIP-immunoreactive. Taken together these results in the rabbit brain emphasize the predominant localization of DSIP-like immunoreactivity in areas related to the hypothalamic neurosecretory systems.

Light and Electron Microscopic Immunocytochemical Evidence that Delta Sleep-Inducing Peptide and Gonadotropin-Releasing Hormone Are Coexpressed in the Same Nerve Structures in the Guinea Pig Median Eminence

“…level, and extend previous immunohistochemical studies in rabbit brain where DSIP-like immunoreactivity has been frequently detected in GnRH-containing neurons [4,13]. Since the first evidence of the colocalization of several neurotransmitters in single neuronal cell bodies [25], many attempts have been made to immunohistochemically demonstrate the colocalization of signal substances in the nervous systems an d /o r peripheral organs [26,27].…”

“…DSIP immunoreactivity is widely distributed in biological fluids, brain and glandular system of several species [4][5][6][7][8]. Besides some sleep-promoting effects [1.…”

“…Besides some sleep-promoting effects [1. 8], DSIP has been reported to influence the secretion of several pituitary hor mones [8][9][10][11], Thus, it has been shown that DSIP could play a role in the release of luteinizing hormone via a hypothalamic site of action [9,12], Previous neuroanatomical studies in the rodent brain indicated that DSIP-immunoreactive fibers and nerve endings were mainly concentrated in the mediobasal hy pothalamic areas [4,6]. It has been further shown that in the rabbit basal forebrain and anterior hypothalamus, most, if not all, gonadotropin-releasing hormone-(GnRH)-containing cell bodies displayed DSIP-like immunoreactivity [13].…”

Colocalization of Delta Sleep Inducing Peptide and Luteinizing Hormone Releasing Hormone in Neurosecretory Vesicles in Rat Median Eminence

“…Staining was not seen in controls using preimmune serum or secondary antibodies alone. Characteristics and details o f preparation of primary antibodies have been extensively described elsewhere [10,11]. Antiserum to DSIP was inactivated by preincubation with synthetic DSIP, but not with LH-RH and pre-pro-LH-RH precursor fragments, adrenacorticotropic hor mone and derivative fragments, thyrotropin-releasing hormone, vaso pressin, angiotensin II, and leukotriene C4 previously immunohistochemically localized within LH-RH neurons [22], Preincubation of anti serum to LH-RH with LH-RH totally abolished the immunoreactivity, whereas preincubation with DSIP or the peptidic hormones mentioned above had no effect.…”

Induction of Pituitary Cell Type Differentiation by Delta Sleep-Inducing Peptide

“…Immunoreactive DSIP has been found in biological fluids, the brain and endocrine glands of several species [6][7][8]. Recent immu nocytochemical studies using light and electron microsco-py have shown that in the adult DSIP colocalizes with GnRH in neurons of several species including man [9], rabbit [10], guinea pig [11] and rat [12].…”