PrRP, also known as prolactoliberin, is a bovine hypothalamic extract neurohormone that stimulates prolactin synthesis in a rat pituitary adenoma cell line and lactating rat pituitary cells. PrRP has been shown to control the intake of food and energy expenditure, but it may also have a role in stress sensitivity, reproduction, cardia productivity, secretion of endocrine components, and lately, neuroprotective characteristics, among others. The current study was performed to identify if prolactin-releasing peptide (PrRP) had any effect in increasing anxiety clinical features in rats as an animal model. The study included 114 Wistar handling-acclimated male rats (160 gm, 2 months old); divided randomly into three major groups. The rats were divided randomly into three major groups (38-control animals (38C), and 38-PrRP animals (38P), both were examined using the EPM test to test for stress-related signs, such as fear of height (5 mins duration for each rat). The maze was cleaned with water to eliminate the previous rat odor after the experiment for each rat was completed. The tests were performed between 13:00 to 17:00 of the day. Then, a week later, 38 (19-PrRP animals (19P) and 19-control animals (19C)) were examined using the SP test conducted between 13:00 to 16:00 of the day. Fifteen minutes before EPM, the 38C received intranasal 0.9%-10µl NaCl (per nostril), and 38P received intranasal 10-10mol/l-10 µl PrRP (per nostril), and the anxiety-related signs, such as time spent in open arms (less time means more anxious), during the EPM test were recorded. The 19P and 19C received 10-10mol/l-10µl PrRP and 0.9%-10µl NaCl, respectively, (intranasal, per nostril, and 15 minutes before the SP test, where a stranger rat was placed in a specific cage in front of each of the 19P and 19C animals in a separate cage, in which both cages provided visual and olfactory but no confrontational contact). The results showed that PrRP significantly (P˂0.05) decreased the time spent by the treated rats on the open arms. In addition, PrRP revealed significant (P˂0.05) decreases in the time spent close to the stranger rat, which means increased anxiety levels. The current findings revealed that prolactin-releasing peptide increases anxiety and decreases sociality in the studied male rats. |
- Dodd GT, Luckman SM. Physiological Roles of GPR10 and PrRP Signaling. Front Endocrinol (Lausanne). 2013;4:20.
- Lin SH. Prolactin-releasing peptide. Results Probl Cell Differ. 2008;46:57-88.
- Prazienkova V, Popelova A, Kunes J, Maletinska L. Prolactin-Releasing Peptide: Physiological and Pharmacological Properties. Int J Mol Sci. 2019;20(21).
- Tachibana T, Sakamoto T. Functions of two distinct "prolactin-releasing peptides" evolved from a common ancestral gene. Front Endocrinol (Lausanne). 2014;5:170.
- Davenport AP. Peptide and trace amine orphan receptors: prospects for new therapeutic targets. Curr Opin Pharmacol. 2003;3(2):127-34.
- Buffel I, Meurs A, Portelli J, Raedt R, De Herdt V, Sioncke L, et al. Neuropeptide FF and prolactin-releasing peptide decrease cortical excitability through activation of NPFF receptors. Epilepsia. 2015;56(3):489-98.
- Pirnik Z, Korinkova L, Osacka J, Zelezna B, Kunes J, Maletinska L. Cholecystokinin system is involved in the anorexigenic effect of peripherally applied palmitoylated prolactin-releasing peptide in fasted mice. Physiol Res. 2021;70(4):579-90.
- Rettori V, Milenkovic L, Riedel M, McCann SM. The role of neuropeptide Y (NPY) in control of gonadotropin and prolactin release in the rat. Gynecol Endocrinol. 1990;4(3):169-79.
- Wang G, Tachibana T, Gilbert ER, Cline MA. Exogenous prolactin-releasing peptide's orexigenic effect is associated with hypothalamic neuropeptide Y in chicks. Neuropeptides. 2015;54:79-83.
- Karnosova A, Strnadova V, Hola L, Zelezna B, Kunes J, Maletinska L. Palmitoylation of Prolactin-Releasing Peptide Increased Affinity for and Activation of the GPR10, NPFF-R2 and NPFF-R1 Receptors: In Vitro Study. Int J Mol Sci. 2021;22(16).
- Penninx BWJH, Pine DS, Holmes EA, Reif A. Anxiety disorders. Lancet. 2021;397(10277):914-27.
- Vos T, Abajobir AA, Abate KH, Abbafati C, Abbas KM, Abd-Allah F, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet. 2017;390(10100):1211-59.
- Robinson GE, Fernald RD, Clayton DF. Genes and social behavior. Science. 2008;322(5903):896-900.
- Tan T, Wang W, Williams J, Ma K, Cao Q, Yan Z. Stress Exposure in Dopamine D4 Receptor Knockout Mice Induces Schizophrenia-Like Behaviors via Disruption of GABAergic Transmission. Schizophr Bull. 2019;45(5):1012-23.
- Takano Y, Ukezono M. An experimental task to examine the mirror system in rats. Sci Rep. 2014;4:6652.
- Turner KM, Peak J, Burne TH. Measuring Attention in Rodents: Comparison of a Modified Signal Detection Task and the 5-Choice Serial Reaction Time Task. Front Behav Neurosci. 2015;9:370.
- Ben-Ami Bartal I, Rodgers DA, Bernardez Sarria MS, Decety J, Mason P. Pro-social behavior in rats is modulated by social experience. eLife. 2014;3:01385.
- Davis XS, Grill HJ. The hindbrain is a site of energy balance action for prolactin-releasing peptide: feeding and thermic effects from GPR10 stimulation of the nucleus tractus solitarius/area postrema. Psychopharmacology (Berl). 2018;235(8):2287-301.
- Morales T, Sawchenko PE. Brainstem prolactin-releasing peptide neurons are sensitive to stress and lactation. Neuroscience. 2003;121(3):771-8.
- Mochiduki A, Takeda T, Kaga S, Inoue K. Stress response of prolactin-releasing peptide knockout mice as to glucocorticoid secretion. J Neuroendocrinol. 2010;22(6):576-84.
- Card JP, Johnson AL, Llewellyn-Smith IJ, Zheng H, Anand R, Brierley DI, et al. GLP-1 neurons form a local synaptic circuit within the rodent nucleus of the solitary tract. J Comp Neurol. 2018;526(14):2149-64.
- McConn BR, Tachibana T, Gilbert ER, Cline MA. Prolactin-releasing peptide increases food intake and affects hypothalamic physiology in Japanese quail (Coturnix japonica). Domest Anim Endocrinol. 2020;72:106464.
|