Capsaicin-induced calcitonin gene-related peptide release from isolated rat stomach measured with a new chemiluminescent enzyme immunoassay.
The peripheral capsaicin-sensitive afferent nerve has been reported to play an important role in gastroprotection and to release a calcitonin gene-related peptide (CGRP). We developed a new chemiluminescent enzyme immunoassay (CLEIA) for CGRP and measured capsaicin-induced CGRP release from the isolated and inverted rat stomach. The basal CGRP release from the stomach was 0.40 +/- 0.02 pg/mg wet weight in a 30-min incubation. Capsaicin (1 x 10(-8)-1 x 10(-5) M) stimulated CGRP release in a concentration-dependent manner. In the stomach from rats with defunctionalization of afferent neurons, the levels of the basal and capsaicin-induced CGRP release were below the limit of detection. On the other hand, the capsaicin-induced CGRP release was not blocked by tetrodotoxin treatment. The gangliosym-pathectomy abolished the increase in the CGRP levels. However, the capsaicin-induced CGRP release was not affected by pretreatment with 6-hydroxydopamine, a neurotoxin that causes a complete degeneration of adrenergic nerve terminals. In conclusion, the CLEIA system may be useful for detecting the released CGRP and studying the activity of capsaicin-sensitive nerves, particularly the CGRP-containing nerves. Our results also confirmed that although the CGRP-containing nerve runs in the sympathetic nerve trunk, the activity of the nerve is not affected by adrenergic nerves, and the capsaicin-induced CGRP release may be attributable to the tetrodotoxin-resistant component.
Inaba
N
N
Pharmaceuticals Research Laboratories, Fujirebio Inc., Tokyo, Japan.
Shibata
M
M
Onodera
S
S
Tanaka
M
M
Suzuki
T
T
Kase
N
N
Yamaura
T
T
D018663:Adrenergic Agents / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis*; D002211:Capsaicin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005753:Gastric Mucosa / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D016627:Oxidopamine / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000187:drug effects* / Q000294:innervation; D013564:Sympathetic Nervous System / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology
D018663:Adrenergic Agents; D013779:Tetrodotoxin; D016627:Oxidopamine; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin