Abstract: A compound having the following formula (II) or its pharmacologically acceptable salt is used as a P2X4 receptor antagonist: in which R11 represents hydrogen or an alkyl group having 1-8 carbon atoms; R21 represents an alkyl group having 1-8 carbon atoms, an alkoxy group having 1-8 carbon atoms, an alkyl group having 1-8 carbon atoms and having 1-3 halogen substituents, or hydroxyl; and R31 is hydrogen or a halogen atom.

Abstract: A compound having the following formula (II) or its pharmacologically acceptable salt is used as a P2X4 receptor antagonist: in which R11 represents hydrogen or an alkyl group having 1-8 carbon atoms; R21 represents an alkyl group having 1-8 carbon atoms, an alkoxy group having 1-8 carbon atoms, an alkyl group having 1-8 carbon atoms and having 1-3 halogen substituents, or hydroxyl; and R31 is hydrogen or a halogen atom.

Abstract: An N-substituted N-(4-piperininyl)amide derivative represented by the following formula (I): (wherein R1 represents C1-6 alkyl, furyl, etc.; R2 represents amino, acetylamino, ureido, etc.; R3 represents hydrogen, C2-8 alkoxycarbonyl, etc.; R4 represents optionally substituted phenyl, etc.; R5 represents hydroxyl, benzyloxy, etc.; R6 represents hydrogen or methyl; and m is 1 or 2) or a salt of the derivative, and an analgesic containing the derivative or salt.

Abstract: Disclosed is a novel peptide having one of the formulae: ##STR1## (A and B are the amino acids: wherein if A is D- or L-Pro, B is Hat or Cit;if A is D-Pro, B is D-Arg, andif B is D- or L-Arg, A is Sat, Pip, Aze or Arg)Asn-A-L- (D-)Pro-Arg- (Gly)n (A is Set, Thr or Ala, n is 1 or 0)A-Ser-Pip-Arg (A is Pro-Asn-, Asn- or Pro-) ##STR2## (A is cyclopentylcarbonyl, Pro or pGlu; B is Gly or .beta.-Ala, W is a hydrogen atom or a group having the formula:or a peptide having the formula: ##STR3## wherein A and B have the same meanings as mentioned above, respectively pGlu-Asn-Ser-A-B-(Gly)n (A is Aze, D- or L-Pro, Pip or Sat, B is D- or L-Arg, Cit, Hat, Lys or Orn, n is 1 or 0) andPro- (Ash)m-Set-L- (D-)Pro-Arg- (Gly) n (m and n are independently 0 or 1)their functional derivatives, and pharmaceutically acceptable salts thereof.

Abstract: A novel peptide derivative having the formula: ##STR1## wherein A between Pro and Q.sup.2 is Arg or Lys: Q.sup.1 is pGlu or H; Q.sup.2 is --Gly--OH or OH; Y.sup.1 is H or --CO--T and Y.sup.2 is OH or T; wherein T is a thiamine derivative group is disclosed. The peptide derivative shows a remarkable nootropic effect.

Abstract: A peptide having one of the following formulae (I), (II), (III) and (IV): ##STR1## or its functional derivatives, and a pharmaceutically acceptable salt thereof are disclosed. These peptides have a nootropic effect and are effective as antidementia agents.

Abstract: Disclosed is a novel peptide having one of the formulae: ##STR1## (A and B are the amino acids: wherein if A is D- or L-Pro, B is Har or Cit;if A is D-Pro, B is D-Arg, andif B is D- or L-Arg, A is Sar, Pip, Aze or Arg)Asn-A-L-(D-)Pro-Arg-(Gly).sub.n(A is Ser, Thr or Ala, n is 1 or 0)A-Ser-Pip-Arg(A is Pro-Asn-, Asn- or Pro-) ##STR2## (A is cyclopentylcarbonyl, Pro or pGlu; B is Gly or .beta.-Ala, W is a hydrogen atom or a group having the formula: or a peptide having the formula: ##STR3## wherein A and B have the same meanings as mentioned above, respectivelypGlu-Asn-Ser-A-B-(Gly).sub.n(A is Aze, D- or L-Pro, Pip or Sar, B is D- or L-Arg, Cit, Har, Lys or Orn, n is 1 or 0) andPro-(Asn).sub.m -Ser-L-(D-)Pro-Arg-(Gly).sub.n(m and n are independently 0 or 1)their functional derivatives, and pharmaceutically acceptable salts thereof.