RGD Reference Report - NK-1 receptors in the rostral ventromedial medulla contribute to hyperalgesia produced by intraplantar injection of capsaicin. - Rat Genome Database

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NK-1 receptors in the rostral ventromedial medulla contribute to hyperalgesia produced by intraplantar injection of capsaicin.

Authors: Pacharinsak, C  Khasabov, SG  Beitz, AJ  Simone, DA 
Citation: Pacharinsak C, etal., Pain. 2008 Sep 30;139(1):34-46. Epub 2008 Apr 14.
RGD ID: 2304276
Pubmed: PMID:18407414   (View Abstract at PubMed)
DOI: DOI:10.1016/j.pain.2008.02.032   (Journal Full-text)

The rostral ventromedial medulla (RVM) is an area of the brainstem involved in the descending modulation of nociception at the level of the spinal cord. Although the RVM is involved in the inhibition or facilitation of nociception, the underlying mechanisms are not understood. Here we examined the role of the neuropeptide substance P and neurokinin-1 (NK-1) receptors located in the RVM on withdrawal responses evoked by mechanical and heat stimuli applied to the rat hindpaw under normal conditions and during hyperalgesia produced by capsaicin. The mechanical withdrawal threshold was obtained using von Frey monofilaments applied to the plantar surface of the hindpaw. Sensitivity to heat was determined by measuring the latency to withdrawal from radiant heat applied to the plantar surface. Mechanical and heat hyperalgesia were defined as a decrease in withdrawal response threshold or latency, respectively. Rats were prepared with a chronic cannula and either vehicle or the NK-1 receptor antagonists, L-733,060 or RP-67580, was injected into the RVM. Paw withdrawal responses were obtained before and after RVM injection, and then at 5, 30, and 60 min after an intraplantar injection of capsaicin (10 microg). Injection of the NK-1 antagonists at doses of 0.5 pmol or higher did not alter withdrawal responses to mechanical or heat stimuli under normal conditions but reduced the duration of nocifensive behavior and the mechanical and heat hyperalgesia produced by capsaicin. These findings suggest that the activation of NK-1 receptors in the RVM contributes to the hyperalgesia produced by capsaicin.

RGD Manual Disease Annotations    Click to see Annotation Detail View

Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
TACR1HumanPain  ISOTacr1 (Rattus norvegicus) RGD 
Tacr1RatPain  IMP  RGD 
Tacr1MousePain  ISOTacr1 (Rattus norvegicus) RGD 

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Tacr1Ratbehavioral response to pain  IMP  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Tacr1  (tachykinin receptor 1)

Genes (Mus musculus)
Tacr1  (tachykinin receptor 1)

Genes (Homo sapiens)
TACR1  (tachykinin receptor 1)

Additional Information