Professor Hugh Piggins (BSc, PhD) - postgraduate opportunities

 

Endocannabinoid Regulation of the Circadian Clock Neural Network

Self-sustaining daily or circadian rhythms in physiology and behaviour such as metabolism or the sleep-wake cycle arise because a neuronal network in our brain functions as an intrinsic body clock. This daily clock is localized to cells in the suprachiasmatic nuclei (SCN) of the hypothalamus. Here some (but not all) neurons contain the intracellular molecular clock and so function as autonomous cellular oscillators. These individual clock neurons synchronize together and regulate brain centres controlling cognition, motivation, arousal, thermoregulation, and hormone release as well as influencing peripheral physiology. In turn, the SCN are responsive to a variety of brain chemicals and environmental sensory signals and it is through these inputs that the SCN itself is synchronized to the external world. Very recently it was shown that endogenous cannabinoids, molecules that resemble the psychoactive constituents of cannabis, could influence the activity of cells in SCN. Exactly how these endogenous cannabinoids regulate SCN neuronal activity and the intracellular clock is unknown. Using experimental compounds that are selective for cannabinoid receptors, this project will employ state of the art electrophysiological and bioimaging approaches to directly determine how activation and blockade of cannabinoid signalling pathways alters SCN neuronal and molecular clock activities. Through this PhD, the student will receive training in patch-clamp electrophysiology and analysis of bioluminescence and fluorescent reporter constructs.

  •  Acuna-Goycolea C, Obrietan K, and van den Pol A (2010) Cannabinoids excite circadian clock neurons. Journal of Neuroscience 30: 10061-10066.
  • Belle MDC, Diekman C, Forger D, and Piggins HD (2009) Daily electrical silencing in the mammalian circadian clock. Science 326: 281-284.
  • Brown TM and Piggins HD (2007) Electrophysiology of the suprachiasmatic circadian clock. Progress in Neurobiology 82: 229-255.
  • Guilding C, Hughes ATL, and Piggins HD (2010) Circadian oscillators in the epithalamus. Neuroscience 169: 1630-1639.
  • Hughes ATL, Guilding C, Lennox L, Samuels RE, McMahon DG, and Piggins HD (2008) Live imaging of altered period1 expression in the suprachiasmatic nuclei of Vipr2-/- mice (2008) Journal of Neurochemistry 106: 1646-1657.

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