Fasciculin II, a protein inhibitor of acetylcholinesterase, tested on central synapses of Aplysia.
Fasciculin II, a potential inhibitor of acetylcholinesterase (AChE), was tested on two types of Aplysia cholinergic receptors: H type, opening Cl- channels; and D type, opening cationic channels. Evoked postsynaptic inhibitory responses and responses to ionophoretic application of acetylcholine (ACh) or carbachol onto H-type receptors were potentiated in the presence of fasciculin II at 10(-9) M, whereas the same concentration of this drug was without effect on the evoked postsynaptic excitatory responses or on the application of ACh or carbachol on D-type receptors. The observed effects of fasciculin II were identical to those obtained with other inhibitors of AChE on the same preparation. The facilitatory effect on the carbachol response in H-type cells indicates that fasciculin II, as other AChE inhibitors, does not act on H-type synapses solely by blocking the hydrolysis of ACh. We concluded that fasciculin II was a good inhibitor of acetylcholinesterase on neuronal preparations in vivo. The results are further discussed as a new element in favor of a previously proposed hypothesis of a molecular interaction between AChE and ACh H-type receptors.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001048:Aplysia; D002217:Carbachol / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D004546:Elapid Venoms / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects; D011950:Receptors, Cholinergic / Q000145:classification / Q000187:drug effects; D013569:Synapses / Q000187:drug effects* / Q000502:physiology
D002800:Cholinesterase Inhibitors; D004546:Elapid Venoms; D011950:Receptors, Cholinergic; C044937:fasciculin; D002217:Carbachol; D000109:Acetylcholine