Structure-activity relationships of benzylidene anabaseines in nicotinic acetylcholine receptors of cockroach nerve cords.
Ten analogues of 6'-chloro-3-benzylideneanabaseine (CBA) bearing substituents at the ortho- and the para-positions of the phenyl group were synthesized, together with two related compounds. The affinity of the synthesized compounds for nicotinic acetylcholine receptors (nAChRs) in the nerve cord of the American cockroach (Periplaneta americana L.) was examined by the radioligand binding assay using [(3)H]epibatidine (EPI), a nAChR agonist. All 12 tested compounds inhibited [(3)H]EPI binding, showing K(i) values ranging from 14.6 to 6830nM. The potency variation of para-substituted CBA analogues was explained by the steric (Delta B(1)) and electronic (sigma(p)) parameters of the para-substituents, or by the steric parameter and the charge of the N1 nitrogen atom (qN(1)). Among the CBA analogues, only two compounds containing a dimethylamino group and a methoxy group at the para-position showed high insecticidal activity against the German cockroach (Blattella germanica) when injected after pretreatment with metabolic inhibitors. High-affinity analogues of CBA might be suitable probes for use in classifying and characterizing insect nAChR subtypes.
Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan.
Israt
I
Sultana
Izumi
I
Ikeda
Yoshihisa
Y
Ozoe
D000691:Anabasine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D000818:Animals; D001597:Benzylidene Compounds / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000493:pharmacokinetics; D003058:Cockroaches / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D009026:Mortality; D009420:Nervous System / Q000187:drug effects; D018722:Nicotinic Agonists / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D010944:Plants; D011725:Pyridines / Q000493:pharmacokinetics; D021281:Quantitative Structure-Activity Relationship; D011869:Radioligand Assay; D011978:Receptors, Nicotinic; D012044:Regression Analysis
D001597:Benzylidene Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007306:Insecticides; D018722:Nicotinic Agonists; D011725:Pyridines; D011978:Receptors, Nicotinic; C091713:anabaseine; D000691:Anabasine; C082748:epibatidine