Lecture 6 - Pineal Gland

Retinitis pigmentosa (RP) is a disease that causes deterioration of the retinas of the eyes. Describe the impact RP would have on melatonin levels.

The retina is important for melatonin production because it senses light. Bright light inhibits the production of melatonin, whereas low light levels promote the production of melatonin. Therefore, deterioration of the retinas would most likely disturb the sleep-wake pattern because melatonin production would be elevated.

The production of melatonin is inhibited by: A. declining levels of light B. exposure to bright light C. the secretion of serotonin D. the activity of pinealocytes

exposure to bright light

What are some disorders of the pineal gland?

Depression, peptic ulcers, and sexual dysfunction may be exacerbated by a deficiency of melatonin. Stress and dietary habits may lead to deficiencies of both serotonin and melatonin. Melatonin inhibits the release of cortisol via the release of vasotocin. Abnormal circadian rhythms of cortisol may occur in states of decreased melatonin. A circannual rhythm of melatonin has troughs associated with peaks in the incidence of peptic ulcers and psychotic depression. Psychotic depression is an apparent disorder of the locus ceruleus and/or dorsal raphe nucleus. ADHD?

What are some important considerations of melatonin use?

If you're pregnant, trying to become pregnant, or nursing, talk to your doctor before using melatonin supplements. Additionally, melatonin may interact with the following medications and groups of medications: fluvoxamine (Luvox) nifedipine (Adalat CC) birth control pills blood thinners, also known as anticoagulants diabetes medications that lower blood sugar immunosuppressants, which lower the activity of the immune system

What is melatonin?

Interestingly, children have higher melatonin levels than adults, which may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty. Antioxidant role of melatonin? is the subject of current research. Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep

What are pineal cysts?

Pineal cysts are relatively common and may be found by chance in up to 10% of people who have a head CT scan or MRI.[2] In most cases, a pineal cyst does not cause signs or symptoms Treatment is usually only considered when a cyst causes symptoms. Treatment may involve open or stereotactic removal of the cyst, stereotactic aspiration, and/or CSF diversion. Symptoms include headaches (the most common symptom), hydrocephalus, disturbances in vision, and eye problems related to not being able to look upwards, and in some instances downwards as well (Parinaud syndrome). Although rare, people with symptomatic pineal cysts may have other symptoms such as difficulty moving (ataxia), mental and emotional disturbances, vertigo, seizures, sleep (circadian rhythm) troubles, vomiting, hormonal imbalances that may cause precocious puberty, or secondary parkinsonism.

Seasonal affective disorder (SAD) is a mood disorder characterized by, among other symptoms, increased appetite, sluggishness, and increased sleepiness. It occurs most commonly during the winter months, especially in regions with long winter nights. Propose a role for melatonin in SAD and a possible non-drug therapy.

SAD is thought to occur in part because low levels and duration of sunlight allow excessive and prolonged secretion of melatonin. Light therapy—daytime exposure to very bright lighting—is one common therapy.

How does the pineal gland regulate bone metabolism?

Studies in mice suggest that the pineal-derived melatonin regulates new bone deposition. Pineal-derived melatonin mediates its action on the bone cells through MT2 receptors. This pathway could be a potential new target for osteoporosis treatment as the study shows the curative effect of oral melatonin treatment in a postmenopausal osteoporosis mouse model.[34] Some studies show that the degree of pineal gland calcification is significantly higher in patients with Alzheimer's disease vs. other types of dementia.[38] Pineal gland calcification may contribute to the pathogenesis of Alzheimer's disease and may reflect an absence of crystallization inhibitors.[38] Calcification of the pineal gland has also been found to be closely associated to certain types of migraines as well as cluster headaches

What is the pineal gland?

produces melatonin, a serotonin-derived hormone modulates sleep patterns More light on retinas = decreased melatonin as light levels decline—such as during the evening—melatonin production increases, boosting blood levels and causing drowsiness lights at night , TV etc effects? Affect appetite Temperature regulation