Intrathecal injection of capsaicin can be used as a behavioural nociceptive test in mice.
Intrathecal injections in mice of substance P (SP), capsaicin and kainic acid elicited a behavioural response similar to that caused by noxious stimulation. Although the agents have different mechanisms of action, they showed a similar response, consisting of biting, scratching and licking the caudal parts of the body. Activation of adenosine receptors in the spinal cord with 5-N-ethylcarboxamide adenosine (NECA) had no effect on the response to substance P or to kainic acid, but reduced the response to capsaicin. It is concluded that different substances, injected intrathecally, can be used to differentiate between pre- and postsynaptic induced nociceptive behaviour, and that this assay may be valuable in assessing central antinociceptive effects of various drugs, especially those affecting systems modulated by substance P.
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology*; D007278:Injections, Spinal; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D051379:Mice; D010147:Pain Measurement / Q000379:methods*; D011983:Receptors, Purinergic / Q000187:drug effects; D013373:Substance P / Q000502:physiology*
D011983:Receptors, Purinergic; D013373:Substance P; D019830:Adenosine-5'-(N-ethylcarboxamide); D000241:Adenosine; D002211:Capsaicin; D007608:Kainic Acid