dopamine icon logo on blue circle with brush texture

acetylcholine adenosine adrenaline anandamide anatomy badge biology brush care catecholamine cell chemical depression design diagram disease dopamine education emotion epinephrine flat graphic health histamine hormone icon illustration logo medicine molecule mood narcotic neuron neurotransmitter nitric norepinephrine opioid oxytocin peptide scheme science serotonin sign signal somatostatin structure symbol synapse vector web