translate English to French: Protection experiments showed that polar ligands (Cch, CD) offered protection against BDF antagonism of nonpolar ligand (alkyl-trimethylammonium) responses that decreased with alkyl chain length, but that nonpolar ligands afforded strong protection for both polar and nonpolar activity that was indpendent of chain length.
Les expériences de protection indiquent que les substances polaires (Cch, CD) offrent une protection contre l'action antagonistique du BDF pour les réponses aux substances non polaires (alkyl-triméthylammonium) qui diminuent en fonction de la longueur de la chaine alkyl.