Which of the following synaptic transmitter is NOT a peptide, polypeptide or protein

D. i.e. (Serotonin) (95 - 96- Ganong 22nd) (1081-82- A.K. Jain 3rd)* Dopamine, Norepinephrine, Epinephrine, Serotonin. Histamine are AMINES* Polypeptides are - Substance P*, other tachykinins, Vasopressin, oxytocin, CRH, TRH, GRH,Somatostatin, GnRH, Endothelins, /3-Endorphin*, Endomorphins Enkephalins*, Dynorphins,Cholecystokinin (CCK-4 and CCK-8). VIP, Neurotensin, Gastrin releasing peptide, Gastrin, Motilin,Secretin, Glucagon derivatives, Calcitonin gene related peptide - a, Neuropeptide y, Activins, Inhibins,Angiotensin II. FMRF amide, Galanin, ANP, BNP,* Substance P - is transmitter for afferent neurons that relay sensory information into the CNS and is though to be invoved in the transmission of nociceptive (pain producing) stimuli.* Enkephalins and Endorphins - role in regulating pain, in eating and drinking behaviour, in central regulation of the CVS, and in cell development