In the guinea pig distal colon, calcitonin gene-related peptide (CGRP, 0.1-30 nM) produced a concentration-dependent inhibition in electrically-evoked nonadrenergic noncholinergic (NANC) contractions and exogenous substance P-induced contractions. Both the inhibitory actions of CGRP were insensitive to human CGRP(8-37) (1-3 microM), a CGRP1 receptor antagonist. These results indicate that in th...

The present study was undertaken to look for the effect of chloroethylclonidine (CEC) on prejunctional alpha-2 autoreceptors of the canine saphenous vein. The effect was tested on tritium overflow evoked by electrical stimulation from tissues preloaded with 0.2 mM H-norepinephrine. Yohimbine (3–300 nM) and CEC (1–125 mM) increased and UK-14,304 reduced the overflow of tritium evoked by 300 puls...

The development of drugs which stimulate selectively the prejunctional dopamine receptor has become a major challenge in recent years1,2), These autoreceptor agonists decrease synthesis and release of dopamine (OA), Thus, the symptoms of schizophrenia originated from dopamine hyperactivity in the mesolimbic system should be reduced. On the other hand, it has been shown that OA autoreceptor agon...