Prolactin-releasing peptide is a potent mediator of stress responses in the brain through the hypothalamic paraventricular nucleus.
The effects of i.c.v. administration of prolactin-releasing peptide on neurons in the paraventricular nucleus of rats and plasma corticosterone levels were examined by measuring changes in Fos-like immunoreactivity, c-fos mRNA using in situ hybridization histochemistry, and plasma corticosterone using a specific radioimmunoassay. Approximately 80% of corticotropin-releasing hormone immunoreactive cells exhibited Fos-like immunoreactivity in the parvocellular division of the paraventricular nucleus 90 min after i.c.v. administration of prolactin-releasing peptide. The greatest induction of the c-fos mRNA expression in the paraventricular nucleus was observed 30 min after administration of prolactin-releasing peptide, and occurred in a dose-related manner. Plasma corticosterone levels were also significantly increased 30 min after administration of prolactin-releasing peptide. Next, the effects of restraint stress, nociceptive stimulus and acute inflammatory stress on the expression of the prolactin-releasing peptide mRNA in the dorsomedial hypothalamic nucleus, nucleus of the solitary tract and ventrolateral medulla were examined using in situ hybridization histochemistry for prolactin-releasing peptide mRNA. Restraint stress and acute inflammatory stress upregulated the prolactin-releasing peptide mRNA expression in the nucleus of the solitary tract and ventrolateral medulla. Nociceptive stimulus upregulated the prolactin-releasing peptide mRNA expression in the ventrolateral medulla. Finally, we observed that pretreatment (i.c.v. administration) with an anti-prolactin-releasing peptide antibody significantly attenuated nociceptive stimulus-induced c-fos mRNA expression in the paraventricular nucleus. These results suggest that prolactin-releasing peptide is a potent and important mediator of the stress response in the brain through the hypothalamic paraventricular nucleus.
Mera
T
T
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Fujihara
H
H
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Kawasaki
M
M
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Hashimoto
H
H
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Saito
T
T
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Shibata
M
M
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Saito
J
J
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Oka
T
T
Department of Neurology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Tsuji
S
S
Department of Neurology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Onaka
T
T
Department of Physiology, Jichi Medical School, Tochigi 329-0498, Japan.
Ueta
Y
Y
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan. Electronic address: yoichi@med.uoeh-u.ac.jp.
D000704:Analysis of Variance; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007028:Hypothalamic Hormones / Q000276:immunology / Q000502:physiology*; D007074:Immunoglobulin G / Q000008:administration & dosage; D007213:Indomethacin / Q000008:administration & dosage; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000276:immunology / Q000502:physiology*; D010147:Pain Measurement / Q000379:methods; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D056690:Prolactin-Releasing Hormone; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical / Q000379:methods; D013312:Stress, Physiological / Q000209:etiology / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007028:Hypothalamic Hormones; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D009479:Neuropeptides; C534379:Prlh protein, rat; D056690:Prolactin-Releasing Hormone; D003346:Corticotropin-Releasing Hormone; D051076:Proto-Oncogene Proteins c-fyn; D003345:Corticosterone; D007213:Indomethacin