Biologic activity of the tachykinins on lamb and sheep gallbladder.
In this study, we examined the activity of the tachykinins (TKs) on lamb and sheep isolated gallbladder and whether the TKs are involved in the capsaicin-induced activity in these tissues. Substance P (SP) and physalaemin (PHYS) contracted lamb gallbladder, PHYS-induced striking tachyphylaxis. This tissue was nearly insensitive to neurokinin A (NKA), neurokinin B (NKB), septide, and capsaicin. As in lamb tissues, SP and PHYS both contracted sheep gallbladder although PHYS induced no tachyphylaxis. At doses that had no effect on lamb tissue, NKA, NKB, septide, and capsaicin contracted sheep gallbladder. Our findings indicate that TK receptors differ in adult and young ovine gallbladder. The activity of PHYS on lamb gallbladder could depend on the existence of an unusual binding site, carrying one or more residues critical for the N-terminal sequence present in PHYS but not in SP.
Tucci
Paolo
P
Department of Pharmacology of Natural Substances and General Physiology, University of Rome La Sapienza, Ple Aldo Moro 5, 00185 Rome, Italy. paolo.tucci@uniroma1.it
Bolle
Paola
P
Severini
Cinzia
C
Valeri
Pacifico
P
D000818:Animals; D001665:Binding Sites; D002211:Capsaicin / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005704:Gallbladder / Q000187:drug effects*; D008297:Male; D009132:Muscles / Q000378:metabolism; D015288:Neurokinin A / Q000494:pharmacology; D015287:Neurokinin B / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D010803:Physalaemin / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D018039:Receptors, Tachykinin / Q000096:biosynthesis; D012756:Sheep; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology; D015320:Tachykinins / Q000494:pharmacology*
D010446:Peptide Fragments; D018039:Receptors, Tachykinin; D015320:Tachykinins; D010803:Physalaemin; D013373:Substance P; C054725:septide; D015288:Neurokinin A; D015287:Neurokinin B; D002211:Capsaicin; D011761:Pyrrolidonecarboxylic Acid