and may be either d or l amino acid unless otherwise indicated with the exception of the n terminal amino acid all amino acid abbreviations e g ala in this disclosure have the structure u2014 nh u2014 ci r u2032 u2014 co u2014 wherein r and r u2032 each is independently hydrogen or the side chain of an amino acid e g r u2550 ch 3 and r u2032 u2550 h for ala or r and r u2032 may be joined to form a ring system a peptide of this invention is also denoted by another format e g pro 34 hnpy 1 36 u2014 nh 2 seq id no 83 with the substituted amino acids from the natural sequence placed between the brackets e g pro for gln in hnpy the designation u201c nh 2 u201d in hnpy 1 36 nh 2 seq id no 1 indicates that the c terminus of the peptide is amidated whereas hnpy 1 36 oh seq id no 1 indicates the free acid form the following list of some of the abbreviations used in the present application is provided for ease of reference however any abbreviation used in the instant application not defined herein are not used contrary to the recognized meanings thereof abu u03b1 aminobutyric acid acc 1 amino 1 cyclo c 3 9 alkyl carboxylic acid wherein.