Related Experiment Video
Updated: Jul 31, 2026
11:45
Functional Interrogation of Adult Hypothalamic Neurogenesis with Focal Radiological Inhibition
Published on: November 14, 2013
Morphofunctional changes in the pineal gland during dynamic adaptation to hypothermia
L A Bondarenko1, G I Gubina-Vakulik
1Chronoendocrinology Laboratory, V. Ya. Danilevskii Institute of Problems of Endocrine Pathology, Ukrainian Academy of Medical Sciences, 10 Artem Street, 61002 Khar'kov-2, Ukraine.
Neuroscience and Behavioral Physiology
|May 31, 2003
Summary
Hypothermia stress initially boosts pineal gland melatonin production in rats, but prolonged exposure significantly suppresses its function by reducing active pinealocytes.
Area of Science:
- Neuroscience
- Endocrinology
- Physiology
Background:
- The pineal gland synthesizes melatonin, a hormone crucial for regulating circadian rhythms.
- Stressors, including environmental changes like hypothermia, can impact neuroendocrine functions.
- Serotonin metabolism is a key pathway for melatonin synthesis in the pineal gland.
Purpose of the Study:
- To investigate the effects of acute hypothermia on serotonin metabolism and pineal gland structure in male Wistar rats.
- To characterize the dynamic changes in melatonin production under cold stress.
Main Methods:
- Adult male Wistar rats were exposed to hypothermia (4°C for 3 hours).
- Pineal gland structure and serotonin metabolism pathways were analyzed.
- Melatonin production was measured at various time points during cold exposure.
Main Results:
- Pineal gland's melatonin-forming function exhibited a biphasic response to hypothermia.
- An initial 15-minute increase in melatonin synthesis was observed.
- Prolonged hypothermia (3 hours) led to significant suppression of melatonin production.
- Suppression was attributed to the exclusion of a proportion of pinealocytes from active functioning.
Conclusions:
- Acute hypothermia induces significant, time-dependent alterations in the rat pineal gland's melatonin synthesis.
- The pineal gland's functional capacity is compromised under sustained cold stress due to reduced cellular activity.
Related Concept Videos
01:30Diencephalon: Anatomical Regions
The diencephalon, etymologically translated as 'through brain,' plays an integral role as the conduit between the cerebrum and the vast extent of the nervous system. However, the olfactory system is an exception, as it interfaces directly with the cerebrum. The diencephalon, deeply ensconced beneath the cerebrum, primarily consists of three paired structures — the thalamus, hypothalamus, and epithelamus. It also includes accessory structures such as the subthalamus, which houses the subthalamic...
01:02The Pineal Gland
The pineal gland, a diminutive endocrine structure named for its pinecone-shaped appearance, is situated atop the third ventricle within the diencephalon region of the forebrain. This gland, composed of secretory cells known as pinealocytes arranged in compact cords and clusters around dense particles of calcium salts, plays a pivotal role in hormonal regulation.
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
01:26Thermoregulation
The human body has a sophisticated thermoregulation system that employs negative feedback mechanisms to maintain an optimal core temperature. When the core temperature drops, peripheral and central thermoreceptors send signals to the hypothalamus, activating the heat-promoting center. This center triggers several responses aimed at increasing the core temperature. First, vasoconstriction reduces the flow of warm blood from internal organs to the skin so that the heat is not lost from the skin,...
01:27Major Hormones and Their Functions
Hormones, the biochemical messengers produced by endocrine glands, are pivotal in regulating bodily functions and maintaining homeostasis. Each hormone's balance is crucial; imbalances can lead to significant physiological disruptions. Major hormones include oxytocin, cortisol, epinephrine, estrogen, testosterone, thyroxine, growth hormone, insulin, and glucagon.
Oxytocin, produced in the hypothalamus and released by the pituitary gland, plays a role in social bonding, childbirth, and lactation.
Oxytocin, produced in the hypothalamus and released by the pituitary gland, plays a role in social bonding, childbirth, and lactation.
01:23Cellular Adaptation I: Introduction and Atrophy
Cells can adapt to environmental changes to maintain function and avoid injury, a process called cellular adaptation. Adapted cells exist in a reversible intermediate state with changes in size, number, phenotype, metabolism, or function. These responses help cells meet altered physiological or pathological demands; for example, enlargement of breast and uterine tissues during pregnancy. Early adaptations may enhance function, but persistent stress eventually causes tissue damage.Types of...