Autonomic neuroscience : basic & clinical
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Projections from the nucleus of tractus solitarius (NTS) to the caudal ventrolateral medulla (CVLM) are important in mediating autonomic reflexes. However, little is known about the cellular properties of the CVLM-projecting NTS neurons. In this study, the CVLM-projecting NTS neurons were retrogradely labeled by fluorescent microspheres injected into the CVLM. ⋯ The residual spontaneous and evoked EPSCs were abolished by the nicotinic receptor antagonist mecamylamine and the purinergic P2X receptor antagonist iso-PPADS. Finally, while bicuculline completely blocked the miniature inhibitory postsynaptic currents (IPSCs), the spontaneous and evoked IPSCs were abolished by a combination of bicuculline and strychnine in labeled NTS neurons. Collectively, these data suggest that the CVLM-projecting neurons are a population of neurons with distinctive membrane properties.
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In this study we explored direct and indirect measures of autonomic nervous system function, as well as changes in cardiovascular complexity, during hemorrhagic shock (HS). ⋯ HS led to an increase in RSNA with subsequent withdrawal. LFnu/HFnu increased during HS in association with vagal withdrawal and loss of RRI complexity. RRI complexity may in part reflect vagal modulation of the heart rate. Changes in directly measured tonic sympathetic traffic do not correlate with non-invasive measures of autonomic modulation of the heart.
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The premature population reaching theoretical term suffers from a major deficit in autonomic nervous system (ANS) activity, as can be seen from heart rate variability indices. Whether this autonomic function recovers in the long term is not yet established. Thus, we analyzed and compared ANS activity indices, at birth or at the time of the theoretical term, and at ages 2-3 and 6-7 years, in two populations: a group of 30 premature children and a reference group of 14 full-term age-matched newborns. ⋯ These data suggest a fast ANS maturation in prematures during the two first years of life, with a higher speed of recovery for the parasympathetic arm. Furthermore, compared evolution shows a faster ANS maturation in premature. Potential mechanisms are discussed.
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The study assessed HIV-related and anti-retroviral therapy-induced neuropathy in myelinated and unmyelinated nerve fibers. One hundred consecutive HIV patients were examined clinically and standard nerve conduction velocities were measured. In addition, electrically induced sympathetic skin response (SSR) was assessed in the palms and soles. ⋯ DeltaSSR allows an indirect measurement of C-fiber conduction velocity. In HIV this measure of unmyelinated sympathetic fibers was most sensitive to anti-viral treatment whereas conduction velocity of myelinated somatic fibers was more sensitive to disease-related neuropathy. The results suggest that HIV neuropathy preferably affects myelinated and anti-retroviral therapy unmyelinated fibers.