Synthetic Scotophobin-mediated Passive Transfer of Dark Avoidance

Abstract

A CHEMICAL rather than an electrical mode of long term storage of learned behavioural information was first suggested more than 20 yr ago¹. Experimental means for studying the nature of the storage molecule (by passive transfer from a trained donor to a naive recipient) were suggested by some provocative experiments^2,3. Jacobson et al.³ claimed that the causative factor was RNA. RNA, however, prepared similarly by others but analysed for impurities by a more sensitive method, was clearly contaminated with peptides⁴. Brain RNA labelled with ³²P and injected intraperitoneally (Jacobson et al.'s injection route) does not cross the blood-brain barrier⁵ although it is well known that peptides do get across. The inconsistency of activity of RNA fractions prepared by different investigators⁶ hinted that: (a) RNA might be acting as a carrier for the true active compound and (b) the binding between RNA and such an active compound might be labile.