Comparison of Crude Methanolic CDS Extracts from Various Tissues

Biological significance of agmatine, an endogenous ligand at imidazoline binding sites

“…Modified protocols for CDS preparations have resulted in the isolation of another ’clonidine‐displacing substance‘, for which it has not yet been definitely clarified whether it is different or identical to the substance described by Atlas ( Atlas & Burstein, 1984a , 1984b ; Atlas et al ., 1987 ). Spectroscopic studies and HPLC have shown that this isolated CDS is not noradrenaline, adrenaline, histamine, agmatine, guanosine, GMP, GDP or GDP, but that it represents a guanosine derivative ( Grigg et al ., 1998 ; Parker et al ., 1999a , 1999b ). Functional studies and binding data, however, remain to be performed.…”