“…There are, howe ve r , limitations concerning interpretation of data derived from such procedures. For example, it has been shown that NE, when given so that it passes the blood-brain barrier (intraventricularly or intravenously into animals with immature blood-brain barriers), produces behavioral depression (Spooner & Winters, 1966;Marley, 1966;Mandell & Spooner, 1968). Furthermore, since regional distribution studies have found unequal concentrations of biogenic amines Glowinski, Axelrod, & Iverson, 1966), the major site of action in the central nervous system is not easily determined for substances producing behavioral changes associated with general alteration of biogenic amines.…”