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  • Winter 2011 - Issue Number 85
  • Winter 2011 - Issue Number 85
  • Features

How good is spontaneous sequence analysis at measuring baroreflex sensitivity in man?

Spontaneous sequence analysis (SSA) is a widely used but controversial technique to measure sensitivity of the heart period component of the baroreflex in man. The principal controversy concerns whether all the sequences it finds are random or causal relationships between blood pressure and heart period. Evidence indicates that the data it generates are not substantially contaminated by random relationships. SSA therefore appears more useful than previously supposed and as good as (and no worse than) any other technique for measuring baroreflex sensitivity, but could still be improved.
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‘Fibroblast-like cells’ mediate purinergic neurotransmission in gastrointestinal smooth muscles

Fibroblast-like cells are abundant in smooth muscle tissues, but little is known about the functional role of these cells in normal tissues and their fate in pathophysiological conditions. New genetic animal models now make it possible to isolate fibroblasts from smooth muscle tissues, and physiological and molecular analyses are beginning to reveal the physiological role of these cells in health and disease.
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Mice deficient in endothelin-3 gene lack pain perception from the terminal gastrointestinal tract

In many different types of mammal, endothelin peptides and their endogenous receptors have been shown to play a major role in nociception in a variety of visceral and somatic organs. Here, we report that mice with a genetic mutation in the endothelin-3 gene have a major sensory deficit in a specific class of low-threshold wide dynamic range spinal afferent nerve that innervates the colorectum. Functionally, these mice display a loss of mechano-nociception selectively from the colorectum, whilst pain perception from other internal and somatic organs remains unaffected.
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Is –110°C cold air cryotherapy effective in improving post-exercise recovery in sports people?

Whole body cryotherapy (WBC) involves repeatedly exposing an individual, dressed in minimal clothing, to extremely cold air (–100 to –130°C) for a short period. One specific claim that is often made is that WBC is effective in treating exercise-induced muscle soreness and damage. However, our results suggest that two bouts of WBC were ineffective in improving recovery from eccentric exercise when administered 24 hours after eccentric exercise.
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Central neural circuitry for shivering

Shivering is a fundamental physiological response that occurs in skeletal muscles to produce heat when it is cold or during the development of fever. This response is initiated and maintained by the central nervous system. Recently, we elucidated the central circuitry mechanism that drives shivering. Interestingly, the neural pathway for shivering overlaps anatomically with that for metabolic thermogenesis in brown adipose tissue.
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Axonal filtering as a mechanism of deep brain stimulation in Parkinson’s disease

Deep brain stimulation (DBS) in Parkinson’s disease is a telling example of how the understanding of the basic principles governing basal ganglia function in the normal and diseased brain provided the rationale for a precisely targeted electro-invasive therapy. Nevertheless, the exact beneficial mechanisms of DBS at the cellular, synaptic and systemic level remain elusive. Our research emphasizes attenuation of axonal excitability as an important mechanism of DBS to abrogate pathological firing patterns.
  • Features

Substrates and triggers for the initiation of arrhythmias

The mechanisms by which the spread of electrical waves through the heart often becomes disturbed in patients with electrical and/or structural heart diseases, leading to cardiac rhythm disturbances, remain incompletely understood. We exposed a novel mechanism for arrhythmia initiation, in which areas of abrupt cardiac tissue expansion and alterations in the inward sodium current responsible for cardiac excitation set the stage for spontaneous premature local re-excitation and arrhythmogenesis.
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