Central nervous system labelling composition for intranasal administration and labelling method and screening method using central nervous system labelling composition for intranasal administration

A method of labeling a central nervous system of a living body by dyeing from an olfactory epithelium by way of an olfactory bulb, the method comprising intranasally administering a central nervous system labeling composition such that the composition temporarily remains in a nasal cavity,

• wherein the composition comprises a compound of formula (1):
• where R1 represents an alkyl group;
• each of R3 through R6 independently represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a carboxylic acid group, a sulfonic acid group, a heterocyclic group, an amino group, or a halogen atom, of which R5 and R6 may be bonded to each other to form a ring;
• X1− represents an anionic group;
• and A represents a formula (3) or a formula (4):
• where R2 represents an alkyl group;
• each of R7 through R10 independently represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a carboxylic acid group, a sulfonic acid group, a heterocyclic group, an amino group, or a halogen atom, of which R7 and R8 may be bonded to each other to form a ring;
• Y represents an alkyl group;
• and * represents a binding site.