Pyrazoline derivative or tetrahydropyridazine derivative and medicinal use thereof

A compound represented by the following formula (1) or a pharmacologically acceptable salt thereof:

• 7
• [wherein X1, X2, X3, X4 and X5 may be the same or different and are each a hydrogen atom, an alkyl group of 1 to 6 carbon atoms, a trifluoromethyl group, a halogen atom, a nitro group, an alkyloxy group of 1 to 6 carbon atoms, an alkylthio group of 1 to 6 carbon atoms, an alkylsulfinyl group of 1 to 6 carbon atoms or an alkylsulfonyl group of 1 to 6 carbon atoms;
• Y is a hydrogen atom or an alkyl group of 1 to 4 carbon atoms;
• when X5 is an alkyloxy group, an alkylthio group, an alkylsulfinyl group, an alkylsulfonyl group or an alkyl group, X5 and Y may be bonded to each other to form a 6- or 7-membered ring;
• Q is a methylene group or an ethylene group;
• and Ar is a 2-pyrazyl gorup, a 3-quinolyl group or an unsubstituted or Rn-substituted 3-pyridyl group, each represented by one of the following formulas:
• 8
• (R of Rn is an alkyl group of 1 to 6 carbon atoms or a halogen atom;
• n is an integer of 0 to 4;
• and Rn indicates that the number of R is n)].