the mean ( sd ) concentrations of npy in the guinea pig respiratory tract , as determined by radioimmunoassay of tissue extracts , were : upper trachea 3.3 ( 0.7 ) , lower trachea 2.0 ( 0.5 ) , and major bronchus 3.5 ( 1.1 ) pmol/g .
C0035237
respiratory tract
C0040578
trachea