Synaptosomes from Mammalian Brain

Due to their availability and ease of use, synaptosomes have been widely used in the study of clostridial neurotoxins. These advantages clearly outweigh the disadvantages of the preparation (e.g., hetero- 

Isoloted Nerve Terminals as a Model System for the Study of Botulinum and Tetanus Toxins 199 

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Mouledous, L., Hunt, S., Harcourt, R., Harry, J.L., Williams, K.L. and Gutstein, H.B. (2003) Proteomic analysis of immunostained, laser-capture microdissected brain samples. Electrophoresis 24,296-302. Nagy, A. and Delgado-Escueta, A.V. (1984) Rapid preparation of synaptosomes from mammalian brain using nontoxic isoosmotic gradient material (Percoll). J. Neurochem. 43, 1114-1123. 

Nagy, A., and Delgado-Escueta, A. V., (1984). Rapid Preparation of Synaptosomes from Mammalian Brain Using Nontoxic Isoosmotic Gradient Material (Percoll), ,/ Neurochem. 43 1114-1123. 

Nagy, A. and Delgado-Escueta, A V (1984) Rapid preparation of synaptosomes from mammalian brain using nontoxic isoosmotic gradient material (Percoll) J Neurochem. 43, 1114—1123. 

DDT significantly enhanced veratridine-dependent uptake at all veratridine concentrations above 10 pM, and maximum sodium uptake in the presence of both compounds was achieved at 50 pM, which is the approximate for veratridine alone These findings suggest that , -DDT notuonly enhances veratridine-dependent activation but also increases the potency of veratridine. This result contrasts with the interaction of deltamethrin and veratridine in mouse brain synaptosomes (Figure 1) where the insecticide enhanced activation but did not affect the potency of the activator The only previous report of insecticide-dependent potency shifts in sodium channel activation is in neuroblastoma cells, where pyrethroids increase the potency of batrachotoxin and dihydrograyanotoxin II as sodium channel activators, but do not alter the potency of veratridine (5). These experiments provide the basis for further studies to compare directly the selectivity and sensitivity of sodium channels from mammalian and fish brain in their interactions with insecticides ... 

Fasciculins inhibit AChE from mammals, electric fish, and some snake venoms with Ki values in the pico- to nanomolar range in contrast, avian, insect, and some other snake venom AChEs are relatively resistant, and high micromolar concentrations are required to inhibit mammalian butyrylcholinesterases (BuChE) (Marchot et al, 1993). Dissociation constants of Fasl and Fas3 are two-fold and 60-fold lower, respectively, than that of Fas2 for synaptosomal rat brain. 

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