Adenosine, Caffeine, and Performance: From Cognitive Neuroscience of Sleep to Sleep Pharmacogenetics

An intricate interplay between circadian and sleep-wake homeostatic processes regulate cognitive performance on specific tasks, and individual differences in circadian preference and sleep pressure may contribute to individual differences in distinct neurocognitive functions. Attentional performance appears to be particularly sensitive to time of day modulations and the effects of sleep deprivation. Consistent with the notion that the neuromodulator, adenosine adenosine , plays an important role in regulating sleep pressure, pharmacologic and genetic data in animals and humans demonstrate that differences in adenosinergic tone affect sleepiness, arousal and vigilant attention attention in rested and sleep-deprived states. Caffeine Caffeine -the most often consumed stimulant in the world-blocks adenosine receptors and normally attenuates the consequences of sleep deprivation on arousal, vigilance, and attention. Nevertheless, caffeine cannot substitute for sleep, and is virtually ineffective in mitigating the impact of severe sleep loss on higher-order cognitive functions. Thus, the available evidence suggests that adenosinergic mechanisms, in particular adenosine A2A receptor-mediated signal transduction, contribute to waking-induced impairments of attentional processes, whereas additional mechanisms must be involved in higher-order cognitive consequences of sleep deprivation. Future investigations should further clarify the exact types of cognitive processes affected by inappropriate sleep. This research will aid in the quest to better understand the role of different brain systems (e.g., adenosine and adenosine receptors) in regulating sleep, and sleep-related subjective state, and cognitive processes. Furthermore, it will provide more detail on the underlying mechanisms of the detrimental effects of extended wakefulness, as well as lead to the development of effective, evidence-based countermeasures against the health consequences of circadian misalignment and chronic sleep restriction

Activation of the GABAergic Parafacial Zone Maintains Sleep and Counteracts the Wake-Promoting Action of the Psychostimulants Armodafinil and Caffeine

We previously reported that acute and selective activation of GABA-releasing parafacial zone (PZVgat) neurons in behaving mice produces slow-wave-sleep (SWS), even in the absence of sleep deficit, suggesting that these neurons may represent, at least in part, a key cellular substrate underlying sleep drive. It remains, however, to be determined if PZVgat neurons actively maintain, as oppose to simply gate, SWS. To begin to experimentally address this knowledge gap, we asked whether activation of PZVgat neurons could attenuate or block the wake-promoting effects of two widely used wake-promoting psychostimulants, armodafinil or caffeine. We found that activation of PZVgat neurons completely blocked the behavioral and electrocortical wake-promoting action of armodafinil. In some contrast, activation of PZVgat neurons inhibited the behavioral, but not electrocortical, arousal response to caffeine. These results suggest that: (1) PZVgat neurons actively maintain, as oppose to simply gate, SWS and cortical slow-wave-activity; (2) armodafinil cannot exert its wake-promoting effects when PZVgat neurons are activated, intimating a possible shared circuit/molecular basis for mechanism of action; (3) caffeine can continue to exert potent cortical desynchronizing, but not behavioral, effects when PZVgat neurons are activated, inferring a shared and divergent circuit/molecular basis for mechanism of action; and 4) PZVgat neurons represent a key cell population for SWS induction and maintenance

Recurrent desmoids determine outcome in patients with Gardner syndrome: a cohort study of three generations of an APC mutation-positive family across 30 years

PURPOSE: Screening of Gardner syndrome (GS) patients is tailored towards prevention of colorectal cancer (CRC). However, many patients suffer from desmoid tumors, which are challenging to treat due to invasive growth and local recurrence. The aims of our study were to determine the effectiveness of screening in GS and analyze outcome of desmoid tumors by treatment modality. METHODS: This was a cohort study of a family of 105 descendants with GS. All family members who agreed were screened by endoscopy, and colorectal resection was performed upon pending malignancy. Resectable desmoids were excised, whereas large tumors were treated by a combination of brachytherapy (BT) and radiotherapy (RT). Main outcome measures were the incidence of CRC and overall and disease-specific mortality (ClinicalTrial.gov ID NCT01286662). RESULTS: Thirty-seven of 105 family members have GS. Preventive colorectal resections were performed in 16 patients (15 %), with one death due to gastric cancer. In four patients who denied screening endoscopy, invasive tumors of the colon (three patients) and stomach developed. Of 33 desmoid tumors, 10 (30 %) were located in the mesentery, 17 (52 %) in the abdominal wall, and 6 (18 %) in extra-abdominal sites. Excision of 12 desmoids was performed in eight patients. Four desmoids were treated by BT and RT and showed full or partial remission. CONCLUSIONS: Provided adequate screening, good long-term control of colorectal tumors is achievable. However, desmoid tumors determine survival and quality of life in many patients. Our data suggest good local control using a combination of brachytherapy/radiotherapy in large desmoids unsuitable for surgical resection