Pulsatile intercellular communication

Some of the main examples of biological rhythms of nonelectrical nature are discussed below, among which are glycolytic oscillations (Section III), oscillations and waves of cytosolic Ca + (Section IV), cAMP oscillations that underlie pulsatile intercellular communication in Dictyostelium amoebae (Section V), circadian rhythms (Section VI), and the cell cycle clock (Section VII). Section VIII is devoted to some recently discovered cellular rhythms. The transition from simple periodic behavior to complex oscillations including bursting and chaos is briefly dealt with in Section IX. Concluding remarks are presented in Section X. 

A. Goldbeter, Pulsatile signaling as an optimal mode of intercellular communication, Proc. Bit. Symp. Control Release Bioact. Mater., 22, 107-108 (1995). 

Part IV is devoted to the function of pulsatile signalling in intercellular communication. The function of cAMP pulses in Dictyostelium is first addressed in chapter 8. Experiments have shown that cAMP signals... 

The possible occurrence in the Dictyostelium system of complex oscillatory phenomena such as birhythmicity, bursting and chaos is discussed in chapter 6. The appearance of periodic behaviour in the course of development provides a model for the ontogenesis of biological rhythms. This aspect is treated in chapter 7. Finally, an additional interest of the intercellular communication system of Dictyostelium amoebae is that it allows us to address the question of the physiological function of the periodic phenomenon. This question is dealt with in chapter 8, where the discussion is extended to the role of pulsatile hormone secretion in higher organisms. 

Function of the rhythm of intercellular communication in Dictyostelium hnk with pulsatile hormone secretion... 

Beyond the case of GnRH, the conclusions on the existence of an optimum frequency of pulsatile signalling probably extend to other hormones, as is discussed for the cases of insulin and growth hormone. This chapter ends with a brief discussion of mechanisms imderlying the generation of pulsatile signals in intercellular communication. 

A close link therefore exists between the function of the cAMP rhythm in D. discoideum and that of the hormonal rhythm of GnRH secretion. In both cases, pulsatile signalling represents an optimal mode of intercellular communication, allowing the avoidance of desensitization in target cells. 

Intercellular communication in Dictyostelium, 163-9 optimal mode of, 22 pulsatile signalling in, 21,22 rhythms and, 9,303... 

Pulsatile hormone secretion, see Hormone Pulsatile signal, generation, 342-8 Pulsatile signalling in Dictyostelium, 21,164,305,516 in intercellular communication, 22 see also cAMP signalling in Dictyostelium Hormone Pulsatile stimulation by cAMP, 306,330,331,516 by GH, 339,520 by GnRH, 310,311,335,336 by platelet-derived growth factor (PDGF), 25,452... 

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