3Structure of the Pineal Gland
The pineal gland is made of supportive interstitial cells and hormone-producing pinealocytes. Neurons or nerve cells may affect pinealocytes by secreting neurotransmitters. Nerve fibers could reach the organ through the pineal stalk. They contain several elements, such as vasopressin, oxytocin, histamine, serotonin, orexin, and GABA. The pinealocyte cells contain receptors for all of these neurotransmitters, which indicates the influence of other chemicals that are prevalent in the brain. In human bodies, this influence can be extended beyond the brain area to a group of neurons in the optic ganglia, parasympathetic sphenopalatine, and sympathetic superior cervical ganglia. [3]
