title: Pharmacological characterization of conotoxin lt14a as a potent non-addictive analgesic.
abstract: Conotoxin lt14a is a small peptide consisting of 13 amino acids. It was originally identified from the cDNA of Conus litteratus in the South China Sea. Previous reports showed lt14a exhibited antinociceptive activity using a hot plate-induced pain mouse model and acted as an antagonist of neuronal nicotinic acetylcholine receptors. We confirmed that conotoxin lt14a administration resulted in antinociception activity using a mouse inflammatory pain model and a rat model of mechanically-induced pain. The mRNA expression of c-fos and NOS in the spinal cord of rats was suppressed by lt14a. Labeling of lt14a with an Alexa Fluor 488 ester showed that lt14a was bound to the surface of PC12 cells and that this binding was inhibited by pre-application of the nicotinic acetylcholine receptor (nAChR) antagonist tubocurarine chloride (TUB) and the nAChR blocker hexamethonium bromide (HB). These data confirm previous reports that showed lt14a binds to the surface of PC12 cells via nAChRs with patch clamp whole-cell recordings. Additional results showed that lt14a suppressed extracellular signal-regulated kinase (ERK1/2) phosphorylation in PC12 cells activated by Ach. Our results showed that lt14a did not induce drug dependence but rather suppressed morphine withdrawal symptoms. Our work suggests that lt14a is a novel antinociceptive agent that targets the nAChR receptor without inducing drug dependence.
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Zhenghua
authors.initials: Z
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China. Electronic address: lsswl@mail.sysu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Mengying
authors.initials: M
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Yuwen
authors.initials: Y
authors.lastname: You
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Wuguang
authors.initials: W
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering Research Center of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China; Beijing University of Chinese Medicine, 11 Bei San Huan Dong Road, Beijing, 100029, People's Republic of China. Electronic address: lssxal@mail.sysu.edu.cn.
authors.forename: Anlong
authors.initials: A
authors.lastname: Xu
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D020916:Conotoxins / Q000494:pharmacology*; D017931:DNA Primers / Q000235:genetics; D005557:Formaldehyde; D005786:Gene Expression Regulation / Q000187:drug effects*; D051379:Mice; D019001:Nitric Oxide Synthase / Q000378:metabolism; D016716:PC12 Cells; D010147:Pain Measurement; D010766:Phosphorylation / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000700:Analgesics; D020916:Conotoxins; D017931:DNA Primers; D016760:Proto-Oncogene Proteins c-fos; C514610:lt14a peptide, Conus litteratus; D005557:Formaldehyde; D019001:Nitric Oxide Synthase
keywords: Analgesic; Conotoxin; Drug addiction; Lt14a; nAChR