Can jet lag be avoided? No, not yet, but recent research indicates that there is hope for a cure in the near future.
The neuropeptide, arginine vasopressin, appears to be an important part of regulating our body clock. In a recent volume of the journal Science, Yamaguchi et al. showed that mice lacking receptors for the neuropeptide arginine vasopressin (AVP) are resistant to jet lag.
Jet lag: Everybody who has traveled in airplanes around the globe or between continents through several time zones most likely experienced jet lag. Jet lag can disrupt the mental and physical well-being of the traveler. Therefore, jet lag highlights the importance of our internal "body clock." Unfortunately, so far there is no cure to avoid bodily symptoms caused by jet lag. Scientists now know that jet-lag symptoms arise from a temporal misalignment between the internal circadian clock and external solar time, and that our circadian system can sense and realign to a shifted cycle of light and darkness. New findings suggest that neuropeptide signals in the brain influence and participate in the regulation of the master circadian clock. This could be good news to help overcoming the health symptoms associated with jet lag.
The circadian clock: Biological life, including the life of humans, is regulated by cyclic chemical processes in four dimensions. Humans perceive their surroundings usually as "spacetime", that is, we observe nature and the rooms we live in as three dimensions and the time we spend in them as a fourth dimension. Einstein went to great length to describe the nature of the three spatial dimensions and the impact of the single temporal dimension in his relativity theory. We all experience the cycle of day and night. Furthermore, almost all species exhibit daily changes in their behavior and/or physiology that are influenced by the earth turning on its axis and the daily rhythms of our solar system. However, these changes arise from a timekeeping system present within the organism. The timekeeping system, or biological "clock," enables an organism to anticipate and prepare for the changes in the physical environment that are associated with day and night cycles. This biological clock coordinates the internal temporal organization with the internal changes that take place in the organism. This ensures that the organism will "do the right thing" at the right time of the day. This endogenous circadian clock drives oscillations in physiology and behavior with a period of about 24 hours.
The scientists in Yamaguchi research group found that circadian rhythms of behavior also called locomotor activity, clock gene expression, and body temperature immediately readjusted to phase-shifted light-dark cycles in mice lacking the vasopressin receptors V1a and V1b (V1a-/-V1b-/-). However, the behavior of V1a-/-V1b-/- mice was still coupled to the internal clock. It was found that the internal clock of the mice oscillated normally under standard conditions. The researcher's experiments with suprachiasmatic nucleus slices in culture suggested that interneuronal communication mediated by the vasopressin receptors V1a and V1b confers on the suprachiasmatic nucleus an intrinsic resistance to external perturbation. The pharmacological blockade of vasopressin receptors V1a and V1b in the suprachiasmatic nucleus of wild-type mice resulted in accelerated recovery from jet lag. This highlights the potential of vasopressin signaling as a therapeutic target for management of circadian rhythm misalignment, such as jet lag and shift work.
The neuropeptid arginine vasopressin, also known as vasopressin, argipressin or antidiuretic hormone, is involved in a wide range of physiological regulatory processes, including water reabsorption, the regulation of blood pressure and water, glucose, and salt levels in the blood. Evidence suggests that it also plays an important role in social behavior, sexual motivation and bonding, and maternal responses to stress, as well as emotional status. The vasopressin hormone and the structurally related posterior pituitaty hormone oxytocin, are synthesized in magnocellular neurosecretory cells of the paraventricular nucleus and the supraoptic nucleus of the of the hypothalamus in most mammals. The
peptide has the following amino acid sequence: Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH2. Arginine vasopressin belongs to the family of neurohypophysial hormones. The peptide is derived from a preprohormone precursor molecule that is synthesized in the hypothalamus and stored in vesicles at the posterior pituitary from where it is released into the bloodstream. Before the peptides are released into the circulation on the basis of hormonal and synaptic signals, with assistance from the pituicytes, they are stored in Herring bodies.
Reference
Yoshiaki Yamaguchi, Toru Suzuki, Yasutaka Mizoro, Hiroshi Kori, Kazuki Okada, Yulin Chen,1 Jean-Michel Fustin, Fumiyoshi Yamazaki, Naoki Mizuguchi, Jing Zhang, Xin Dong, Gozoh Tsujimoto, Yasushi Okuno, Masao Doi, Hitoshi Okamura; Mice Genetically Deficient in Vasopressin V1a and V1b Receptors Are Resistant to Jet Lag. Science 342, 85 (2013).