Stimulation of the Extraspinal Peripheral Nervous System

Inflammation is a hallmark of several neurodegenerative disorders including hereditary amyloidogenic transthyretin amyloidosis (ATTRv). ATTRv is an autosomal dominant neurodegenerative disorder with extracellular deposition of mutant transthyretin (TTR) aggregates and fibrils, particularly in nerves and ganglia of the peripheral nervous system. Nerve biopsies from ATTRv patients show increased cytokine production, but interestingly no immune inflammatory cellular infiltrate is observed around TTR aggregates. Here we show that as compared to Wild Type (WT) animals, the expression of several chemokines is highly downregulated in the peripheral nervous system of a mouse model of the disease. Interestingly, we found that stimulation of mouse Schwann cells (SCs) with WT TTR results in the secretion of several chemokines, a process that is mediated by toll-like receptor 4 (TLR4). In contrast, the secretion of all tested chemokines is compromised upon stimulation of SCs with mutant TTR (V30M), suggesting that V30M TTR fails to activate TLR4 signaling. Altogether, our data shed light into a previously unappreciated mechanism linking TTR activation of SCs and possibly underlying the lack of inflammatory response observed in the peripheral nervous system of ATTRv patients.

Download Full-text

Effective Ultrasonic Stimulation in Human Peripheral Nervous System

10.1101/2021.04.22.440931 ◽

2021 ◽

Author(s):

Thomas Riis ◽

Jan Kubanek

Keyword(s):

Nervous System ◽

Peripheral Nervous System ◽

Low Frequency ◽

Controlled Study ◽

Excitable Cells ◽

Low Frequencies ◽

Ultrasound Frequency ◽

Nociceptive Responses ◽

Ultrasonic Stimulation ◽

Stimulation Of

AbstractObjectiveLow-intensity ultrasound can stimulate excitable cells in a noninvasive and targeted manner, but which parameters are effective has remained elusive. This question has been difficult to answer because differences in transducers and parameters—frequency in particular—lead to profound differences in the stimulated tissue volumes. The objective of this study is to control for these differences and evaluate which ultrasound parameters are effective in stimulating excitable cells.MethodsHere, we stimulated the human peripheral nervous system using a single transducer operating in a range of frequencies, and matched the stimulated volumes with an acoustic aperture.ResultsWe found that low frequencies (300 kHz) are substantially more effective in generating tactile and nociceptive responses in humans compared to high frequencies (900 kHz). The strong effect of ultrasound frequency was observed for all pressures tested, for continuous and pulsed stimuli, and for tactile and nociceptive responses.ConclusionThis prominent effect may be explained by a mechanical force associated with ultrasound. The effect is not due to heating, which would be weaker at the low frequency.SignificanceThis controlled study reveals that ultrasonic stimulation of excitable cells is stronger at lower frequencies, which guides the choice of transducer hardware for effective ultrasonic stimulation of the peripheral nervous system in humans.

Download Full-text

A Movement Generated in the Peripheral Nervous System: Rhythmic Flexion by Autotomized Legs of the Stick Insect Cuniculina Impigra

Journal of Experimental Biology ◽

10.1242/jeb.111.1.191 ◽

1984 ◽

Vol 111 (1) ◽

pp. 191-199

Author(s):

U. BÄSSLER

Keyword(s):

Nervous System ◽

Electrical Stimulation ◽

Peripheral Nervous System ◽

Related Species ◽

Action Potentials ◽

Small Diameter ◽

Stick Insect ◽

Muscle Twitch ◽

Single Motor ◽

Stimulation Of

Autotomized legs of the stick insect Cuniculina impigra bend rapidly and rhythmically at the femur-tibia joint. These flexions occur at a frequency 1–6 Hz immediately after autotomy and decrease in frequency and amplitude with time. Each flexion is produced by a burst of 1–14 action potentials in a single motor axon of the flexor tibiae muscle (bursting axon). These rhythmic discharges are generated in a very restricted part of the crural nerve, which contains the bursting axon, close to the autotomy point and appear whenever the nerve is cut in the immediate vicinity of this generator region. Rhythmic flexion can also be elicited by electrical stimulation of the crural nerve. The bursting axon is of small diameter. It innervates all or most of flexor tibiae muscle in which it produces relatively large EPSPs. Each EPSP elicits one muscle twitch. These fuse into a brief tetanus, whose amplitude is proportional to the number of spikes in a burst. Each tetanus produces one flexion. This behaviour does not occur in the autotomized legs of several related species.

Download Full-text

The Role of Peripheral Nervous System in Colour Changes of Bufo Arenarum Hensel

Journal of Experimental Biology ◽

10.1242/jeb.31.4.631 ◽

1954 ◽

Vol 31 (4) ◽

pp. 631-638

Author(s):

A. O. M. STOPPANI ◽

P. F. PIERONI ◽

A. J. MURRAY

Keyword(s):

Nervous System ◽

Peripheral Nervous System ◽

Peripheral Nerves ◽

Secondary Role ◽

Bufo Arenarum ◽

Colour Changes ◽

Stimulation Of

1. Stimulation of the peripheral nerves of Bufo arenarum Hensel produces a partial paling of the skin due to concentration of pigment in the intracutaneous melanophores, and dispersion of guanin-granules in the guanophores. This effect is attributed to the liberation in situ of an adrenergic-like substance. Noradrenalin and the cutaneous secretion (which contains adrenalin and active bases) play no part in the blanching of the skin. 2. The nervous system plays a secondary role in the paling of the skin which follows hypophysectomy. 3. There is no evidence that stimulation of the peripherai nervous system is essential for the colour changes of B. arenarum.

Download Full-text