A comparative study of the actions of alkylpyridinium salts from a marine sponge and related synthetic compounds in rat cultured hippocampal neurones

Table 1 Concentrations of the samples: the values in μg/ml were used in this study to give approximately equivalent numbers of pyridinium rings for each compound investigated. The corresponding values in μM are given below

	Molecular Weight	0.005 μg/ml corresponds to (μM)	0.05 μg/ml corresponds to (μM)	0.5 μg/ml corresponds to (μM)	5 μg/ml corresponds to (μM)	50 μg/ml corresponds to (μM)
Poly-APS	12200^a)	4* 10^-4	4* 10^-3	0.04	0.4	4
Monomer S1	129	3.8* 10^-2	0.38	3.8	38	388
Dimer S2	772	6.5* 10^-3	0.065	0.65	6.5	65
Tetramer S3	1490	3.4* 10^-3	0.034	0.34	3.4	34
Tetramer S4	1268	3.9* 10^-3	0.039	0.39	3.9	39

^a) Mean molecular weight considering natural poly-APS as a 1:1 mixture of the two polymers with n = 29 and n = 99.