Neuropeptide EI (NEI) is an endogenous peptide fragment of rat prepro-melanin concentrating hormone (MCH) that is involved in hormone release, grooming behavior, and motor activity.1 NEI corresponds to amino acids 140-152 of rat prepro-MCH and 131-143 of human, mouse, and rat prepro-MCH. It is expressed in both the central and peripheral nervous systems, localizes to the cytoplasm, and colocalizes with MCH in the CNS.1,2 NEI (1 ?M) reduces thyrotropin-releasing hormone (TRH) release in mediobasal hypothalamus explants.3 Intracerebroventricular administration of NEI increases serum levels of luteinizing hormone (LH) in male rats and in chronically ovariectomized female rats that received estradiol benzoate and progesterone in addition to NEI.4 NEI (1 ?g/animal, i.c.v.) induces excessive grooming behavior and increases locomotor activity in rats, effects that can be blocked by MCH or α-melanocyte-stimulating hormone (α-MSH).5 It also increases the amount of time spent in REM sleep in rats when injected intracerebroventricularly or into the ventrolateral periaqueductal grey (vlPAG).
References:
[1]. Bittencourt, J., and Celis, M.E.Anatomy, function and regulation of neuropeptide EI (NEI)Peptides29(8)1441-1450(2008).
[2]. Bittencourt, J.C.Anatomical organization of the melanin-concentrating hormone peptide family in the mammalian brainGen. Comp. Endocrinol.172(2)185-197(2011).
[3]. Kennedy, A.R., Todd, J.F., Stanley, S.A., et al.Melanin-concentrating hormone (MCH) suppresses thyroid stimulating hormone (TSH) release, in vivo and in vitro, via the hypothalamus and the pituitaryEndocrinology42(7)3265-3268(2001).
[4]. Attademo, A.M., Sánchez-Borzone, M., Lasaga, M., et al.Intracerebroventricular injection of neuropeptide EI increases serum LH in male and female ratsComparative Study25(11)1995-1999(2004).
[5]. Sanchez, M., Baker, B.I., and Celis, M.Melanin-concentrating hormone (MCH) antagonizes the effects of α-MSH and neuropeptide E-I on grooming and locomotor activities in the ratPeptides18(3)393-396(1997).