Paradoxical Sleep (ps) Factors
Shojiro Inoué in Biology of Sleep Substances, 2020
Contrary to the first report that arginine vasotocin (AVT), a pineal hormone, induced SWS in cats,56 Coculescu et al.57,59 demonstrated the REM sleep-enhancing capacity of AVT in humans. Two s.c. injections of AVT (each 1 to 2 μg) at night induced REM sleep at the expense of non-REM sleep in healthy humans (see Figure 7). However, diurnal administration of AVT through continuous i.v. perfusion of 2 to 12 μg in the early morning (between 04.00 and 08.00 h ) or in the afternoon (between 16.00 and 19.00 h), resulted in no sleep-modulatory effect. In contrast, the same Romanian research team reported a tremendous increase in the total amount of nocturnal sleep, both non-REM sleep and REM sleep, after intranasal administration of AVT (10 μg) in healthy subjects and insomniacs.60
The Melanotropic Peptides: Structure and Chemistry
Mac E. Hadley in The Melanotropic Peptides, 1988
The structure and activity relationships of MCH have been investigated by chemical modification, enzymatic digestion and synthesis of a few peptide analogues. A C-terminal cyclic peptide obtained by chymotryptic digestion of salmon prolactin (H-Arg-Cys-Arg-Ala- Thr-Lys-Met-Arg-Pro-Glu-Thr-Cys-OH) exhibited an EC50 of 5 × 10–6M, whereas intact salmon prolactin was inactive. Hypothalamic cyclic peptides such as somatostatin, Argvasopressin, Arg-vasotocin, oxytocin, and isotocin, showed no activity.
Neurohypophysis
Paul V. Malven in Mammalian Neuroendocrinology, 2019
Arginine vasotocin constitutes a molecular compromise, being vasopressinlike at position #8 and oxytocin-like at position #3 (Table 3-1). This molecule is found in neurohypophysial tissue of most submammalian vertebrates, but it also occurs in the neurohypophysis of mammalian fetuses and perhaps in the pineal gland of some adult mammals. The functional role of arginine vasotocin in mammals is unclear, but in bioassays the molecule has both oxytocinergic and vasopressinergic activity.
The Volumetric Changes of the Pineal Gland with Age: An Atlas-based Structural Analysis
Published in Experimental Aging Research, 2022
Minoo Sisakhti, Lida Shafaghi, Seyed Amir Hossein Batouli
The pineal gland is an interhemispheric neuroendocrine organ that, as a small canonical gland of about 100 mm3, along with habenula nuclei is located medially in the epithalamus of the vertebrate brain, and is surrounded by the structures such as the posterior third ventricle, thalami, and the splenium of the corpus callosum. It contains varied categories of cells such as pinealocytes (80% of the gland), astrocytes, microglia, and more recently evidenced pineal neurons and peptidergic neuron-like cells. This circumventricular organ, as a whole apparatus, concludes mechanisms for synthesis and secretion (into the bloodstream and CSF) of the indoleamine melatonin (N-acetyl-methoxytryptamine)-as the most identified one-, as well as the serotonin, arginine, vasotocin, and some forms of the neurosteroids (Beker-Acay et al., 2016; Khavinson & Lin’kova, 2012; J. Park et al., 2018; Sigurdardottir et al., 2016).
Possible roles of brain derived neurotrophic factor and corticotropin releasing hormone neurons in the nucleus of hippocampal commissure functioning within the avian neuroendocrine regulation of stress
Published in Stress, 2021
Hakeem J. Kadhim, Seong W. Kang, Wayne J. Kuenzel
Activation of parvocellular neurons within the avian hypothalamic paraventricular nucleus (PVN) resulted in an increase of corticotropin releasing hormone (CRH) and arginine vasotocin (AVT) (Kuenzel & Jurkevich, 2010). When CRH and AVT reach the anterior pituitary (APit), CRH binds to two G-protein coupled receptors, CRHR1 and CRHR2; AVT or AVP binds to the V1aR and V1bR. They, in turn, stimulate proopiomelanocortin (POMC) synthesis that is further processed to adrenocorticotropic hormone (ACTH) (Bonfiglio et al., 2011). In adrenal glands, ACTH activates the avian interrenal tissue to produce the stress hormone, corticosterone (CORT) (Herman et al., 2016; Romero, 2004). Stress hormone binds to glucocorticoid receptors (GRs) located on different tissues to provide energy for immediate use (McEwen, 2007) as well as to induce a negative feedback that regulates hypothalamic-pituitary-adrenocortical (HPA) axis activity (Keller-Wood, 2015; Chrousos, 2009; Vandenborne et al., 2005). Additionally, CRH neurons were identified in the nucleus of the hippocampal commissure (NHpC), an extra-hypothalamic structure, suggesting that the NHpC may be involved in the regulation of the stress response (Nagarajan et al., 2017a, 2014; Xie et al., 2010).
24 hour patterning in gene expression of pineal neurosteroid biosynthesis in young chickens (Gallus gallus domesticus L.)
Published in Chronobiology International, 2021
Magdalena Chustecka, Natalia Blügental, Pawel Marek Majewski, Iwona Adamska
Although these biosynthetic pathways are well known, their regulation is not fully understood. The activity of enzymes catalyzing synthesis of neurosteroids can be modulated by various mediators. Neurotransmitters, e.g., dopamine (Baillien and Balthazart 1997), γ-aminobutyric acid (Do Rego et al. 2000), glutamate (Balthazart et al. 2006), as well as hormones, e.g., melatonin (Tsutsui et al. 2008), have been demonstrated to decrease enzyme activity, while endogenous benzodiazepines (Do Rego et al. 2007) or vasotocin/mesotocin (Do Rego et al. 2006) enhance it. Further, the functionally broadly ranging E4BP4 transcription factor, which is highly expressed in many tissues, has been detected in the pineal gland (Yin et al. 2017). In mammals and birds, its principal pineal functions are suppression and down-regulation of Period2 (Per2) mRNA, one of canonical clock genes (Doi et al. 2001; Ohno et al. 2007). E4BP4 also induces activation of cholesterol biosynthetic genes, targets for the sterol regulatory element-binding protein transcription factor (SREBP) (Hatori et al. 2011). Moreover, chicken StAR has the functional capacity for clock-driven expression in preovulatory ovarian follicles (Nakao et al. 2007).