Ultradian

Almirall H., Bautista V., Sanchez-Bahillo A, Trinidad-Herrero M. (2001). Ultradian and circadian body temperature and activity rhythms in chronic MPTP treated monkeys. Neurophysiol. Clin. 31, 161-70. 

Naber D., Wirz-Justice A., Kafka M. S., Wehr T. A. (1980). Dopamine receptor binding in rat striatum ultradian rhythm and its modification by chronic imipramine. Psychopharmacology (Berl). 68(1), 1-5. 

Geoffriau, M., Claustrat, B. 8r Veldhuis, J. (1999). Estimation of frequently sampled nocturnal melatonin production in humans by deconvolution analysis evidence for episodic or ultradian secretion. J. Pineal Res. 27, 139-44. 

C. Wagner, S. R. Caplan, and G. S. Tannenbaum, Genesis of the ultradian rhythm of GH secretion A new model unifying experimental observations in rats. Am. J. Physiol. 275, E1046-1054 (1998). 

M. W. Young, An ultradian clock shapes genome expression in yeast. Proc. Natl. Acad. Sci. USA 101, 1118-1119 (2004). 

Schihler Other oscillators are not affected by the heavy water, such as ultradian oscillators. 

The ultradian sleep—wake and temperature rhythm produced by 3rd ventricle infusion of TGFa closely resembles the effect of a focal excitotoxic lesion of SPZ neurons (Lu et al 2001). This ultradian rhythm is normally suppressed by circadian control and is disinhibited when SPZ neurons fail to relay SCN circadian information to sleep—wake circuits. Our results indicate that chronic TGFa administration uncouples SPZ neurons from sleep-regulatory circuits and that SPZ neurons expressing the EGFR transmit circadian information from the SCN to sleep—wake centres, in addition to likely regulating circadian locomotor activity. 

Davanzo, P.A., Krah, N., Kleiner, J., and McCracken, J. (1999) Ni-modipine treatment of an adolescent with ultradian cycling bipolar affective illness. J Child Adolesc Psychopharmacol 9 51— 61. 

Brunet et al. (1990), in an open study, reported positive antimanic effects of nimodipine in six patients with acute mania. Our results showed a much lower response rate, ffowever, our patients were much more refractory by history, were treated in a tertiary referral research center, and generally showed a higher incidence of rapid, ultrarapid, and ultradian cycling patterns than in more traditional studies. Our results, however, are consistent with those of Manna (1991), who reported equal long-term efficacy of nimodipine and lithium monotherapy and greater efficacy on a combination of the two drugs than on either drug alone. 

Post and colleagues (252, 253) have suggested that voltage-gated calcium antagonists, such as nimodipine, may be more effective, especially in treatment-resistant and ultrarapid and ultradian cycling patients (i.e., cycles every several weeks or hours, respectively). This is in part because such agents may penetrate the blood—brain barrier more readily than verapamil. 

The reluctance to place assessments at intervals of 90 min which, at the time, were thought to possibly be overshadowed by an ultradian rhythmic process. 

Lavie P, Scherson A. Ultrashort sleep-waking schedule. I. Evidence of ultradian rhyth-micity in sleepability. Electroencephalogr Clin Neurophysiol 1981 52 163-174. 

Lavie P, Zomer J. Ultrashort sleep-waking schedule. II. Relationship between ultradian rhythms in sleepability and the REM-NONREM cycles and effects of the circadian phase. Electroencephalogr and Clin Neurophysiol 1984 57 35 -2. 

Lavie P. To nap, perchance to sleep—ultradian aspects of napping. In Dinges DF, Broughton RJ, eds. Sleep and Alertness Chronobiological, Behavioral, and Medical Aspects of Napping. New York Raven Press, 1989 99-120. 

Perez-Lloret S, Aguirre AG, Cardinali DP, Toblli JE (2004) Disruption of ultradian and circadian rhythms of blood pressure in nondipper hypertensive patients. Hypertension 44 311-315... 

Le Fur, I. et al., Analysis of circadian and ultradian rhythms of skin surface properties of face and forearm of healthy women, J. Invest. Dermatol., 117, 718, 2001. 

Many hormonal secretion processes also exhibit strong circadian components. This is true, for instance, for cortisol, antidiuretic hormone, and growth hormone. The secretion of growth hormone is markedly increased during the early periods of sleep, and the secretion of antidiuretic hormone also reflects the sleep-wake cycle. The mechanisms underlying these oscillations can often be traced back to cyclical variations in the activity of the central nervous system. At the same time, the circadian rhythm modulates the above-mentioned ultradian oscillations. 

Let us try to illustrate the mechanism-based modeling approach through the process of formulating a model of the ultradian oscillations in human insulin secretion [9], A better understanding of the role and underlying mechanisms of these oscillations is clearly of interest in the design of an optimal treatment of diabetes. 

We conclude that the ultradian insulin oscillations cannot be related to an intermittent supply of glucose. Neither do the oscillations appear to be generated through interaction with counter-regulatory hormones, since analysis of simulta-... 

Fig. 2.1 Examples of ultradian oscillations in human insulin secretion and blood glucose concentration (a) during continuous enteral nutrition and (b) during constant glucose infusion. Closer inspection shows that the glucose oscillations lead the insulin oscillations by a few minutes. Redrawn from [39, 40].

Fig. 2.2 Simulation of a mechanism-based model of ultradian insulin-glucose oscillations. Using independently determined parameters and nonlinear relations, the model displays self-sustained oscillations of the correct period with proper amplitudes and phase relationships. The model also responds correctly to a meal as well as to changes in the rate of glucose infusion.

With such independently determined parameters, the model must now be able to reproduce the experimentally observed characteristics of ultradian oscillations in human insulin secretion, e.g. the observed period, the oscillation amplitudes and phase relations, and the ringing of the insulin secretion in response to a meal. If the model can only produce the desired behavior after minor adjustments of the parameters, such adjustments may be performed. In most cases, however, the model either produces temporal variations in qualitative and semi-quantitative agreement with the empirical results or it does not produce anything that resembles them at all. In the latter case we conclude that the model structure is incorrect, and that a new hypothesis must be formulated. 

Figure 2.2 presents the results obtained with our mechanism-based model of the ultradian insulin-glucose oscillations [9], Although clearly only a preliminary model of the phenomenon, the applied model passes all of the above tests. The model produces self-sustained oscillations of the correct period and proper amplitudes, and the model also responds correctly both to a meal and to changes in the rate of glucose infusion. The next step is to use the model to predict the outcome of experiments that have not previously been performed. To the extent that the model is successful in such predictions, the hypothesis underlying the model structure gains additional support. 

---