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Physiological functions of central GRP and NMB receptors in the modulation of itch sensation in rats
Author(s) -
Su PinYen,
Cheng ChiaChen,
Chen ChangMing,
Ko MeiChuan
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.617.14
Bombesin is a pruritogenic agent that causes the most intense itch scratching activity in rodents and it has high affinity for gastrin‐releasing peptide receptor (GRPr) and neuromedin B receptor (NMBr). The aim of this study was to pharmacologically investigate the roles of GRPr and NMBr in eliciting itch scratching behavior in rats. The intracerebroventricular (i.c.v.) route was selected for drug delivery because the study focused on the supraspinal site of action and it is highly relevant to the scratching site. GRP and NMB were used to characterize the magnitude and duration of scratching. The GRPr (RC‐3095) and NMBr (PD168368) antagonists were used to examine whether each receptor is selective in eliciting scratching. After i.c.v. administration, GRP (0.03–0.3 nmol) and NMB (0.1–1 nmol) dose‐dependently elicited profound scratching. GRP‐induced scratching last for one hour, but NMB‐induced scratching last only for 10 minutes. In addition, i.c.v. pretreatment with RC‐3095 (0.1–1 nmol) and PD168368 (0.3–3 nmol) dose‐dependently antagonized scratching elicited by GRP and NMB, respectively. More importantly, RC‐3095 1 nmol failed to block NMB‐induced scratching and PD168368 3 nmol failed to block GRP‐induced scratching. Cross‐examination of both antagonists demonstrated that activation of central GRPr and NMBr may independently elicit itch sensation in rats (Supported by USPHS grant AR‐059193).