Renal, Cardiac, and Autonomic Effects of Catheter-Based Renal Denervation in Ovine Heart Failure

A growing number of clinical studies suggest that in heart failure renal denervation (RDN) has beneficial effects on the autonomic control of the heart. There is also experimental evidence that surgical RDN improves sodium handling and clearance in heart failure. The aim of this study was to determine the effects of catheter-based RDN on the sympathetic and parasympathetic control of the heart, and salt and water handling capacity of the kidneys, in sheep with established heart failure. A randomized, controlled study was conducted in 10 sheep with heart failure (ejection fraction<40%) induced by rapid ventricular pacing. Sheep underwent either bilateral RDN using the Symplicity denervation system or sham denervation and were studied 1 and 6 weeks after RDN. In established ovine heart failure, at 6 weeks after catheter-based RDN, heart rate significantly decreased, estimates of resting and maximal parasympathetic control of heart rate increased, and cardiac sympathetic nerve activity decreased. Compared with sham denervation, there was an increase in the resting sodium and water excretion 6 weeks after catheter-RDN and an improved ability of the kidneys to excrete a nonhypertensive saline load. After catheter-based RDN, renal norepinephrine levels were reduced by 70% compared with sham denervation. In established heart failure, RDN induced a beneficial shift in both arms of the autonomic nervous control of the heart and improved the ability of the kidneys to excrete sodium and water. Thus, effective catheter-based RDN may be beneficial to both the heart and kidneys in heart failure.

Facilitation of oral sensitivity by electrical stimulation of the faucial pillars

Dysphagia is common in neurological disease. However, our understanding of swallowing and its central nervous control is limited. Sensory information plays a vital role in the initiation of the swallowing reflex and is often reduced in stroke patients. We hypothesized that the sensitivity threshold of the anterior faucial pillar could be facilitated by either electrical stimulation (ES) or taste and smell information. The sensitivity threshold was measured by ES in the anterior faucial pillar region. The measurement was repeated 5 min after baseline. Thirty minutes after baseline, the participants underwent a test for taste and smell. Immediately after the test, the ES was repeated. Thirty healthy volunteers with a mean age of 27 ± 5.1 participated in the trial. Mean sensitivity threshold at baseline was 1.9 ± 0.59 mA. The values 5 min after baseline (1.74 ± 0.56 mA, p = 0.027) and 30 min after baseline (1.67 ± 0.58 mA, p = 0.011) were significantly lower compared to the baseline, but there was no difference between the latter (p = 0.321). After 5 min, a potentially facilitating effect was found on oral sensitivity by ES of the faucial pillar area. Thirty minutes later, this effect was still present.Trial registration Clinicaltrials.gov, NCT03240965. Registered 7th August 2017—https://clinicaltrials.gov/ct2/show/NCT03240965.

Facilitation of Oral Sensitivity by Electrical Stimulation of the Faucial Pillars

BackgroundDysphagia is common in neurological disease. However, our understanding of swallowing and its central nervous control is limited. Sensory information plays a vital role in the initiation of the swallowing reflex and is often reduced in stroke patients. We hypothesized that the sensitivity threshold of the anterior faucial pillar could be facilitated by either electrical stimulation (ES) or taste and smell information.MethodsThe sensitivity threshold was measured by ES in the anterior faucial pillar region. The measurement was repeated 5 minutes after baseline. Thirty minutes after baseline, the participants underwent a test for taste and smell. Immediately after the test, the ES was repeated. ResultsThirty healthy volunteers with a mean age of 27±5.1 participated in the trial. Mean sensitivity threshold at baseline was 1.9mA ± 0.59mA. The values 5 minutes after baseline (1.74mA ± 0.56mA, p=0.027) and 30 minutes after baseline (1.67mA ± 0.58mA, p=0.011) were significantly lower compared to the baseline, but there was no difference between the latter (p=0.321).Conclusion After 5 minutes, a potentially facilitating effect was found on oral sensitivity by ES of the faucial pillar area. Thirty minutes later, this effect was still present.

The primary gasotransmitters and their respective donors in the mission of vision (eye health): a comprehensive overview

Nitric oxide (NO) along with Carbon monoxide (CO) and Hydrogen Sulphide (H2S) are biologically significant gaseous molecules generally called as “gasotransmitters”. At a concentration higher or lower than optimum value may result in toxicity or malfunctioning of mammalian tissues. Soon after the acknowledgment of NO as multifunctional bio-signalling molecule in 1987, many interesting implications of this field emerged out. Meanwhile, several studies have proven the NO-biosynthetic pathway responsible for normal functioning of eye. High intraocular pressure (IOP) has been suggested as the main risk factor in this context and collaborative approach with nitric oxide releasers is said to control IOP and hence the relation with glaucoma. Similar miracles were reflected from several other naturally produced gaseous molecules,viz., CO and H2S after year 1990. The biological roles of both these molecules are now widely accepted and in the current era investigations focused mainly with development of efficient CO and H2S releasing compounds. CO and H2S donors are also said to help in normalising IOP like NO. Therefore the trio-gasotransmitters have collective relation with the ophthalmic homeostasis in association with nervous control. On one hand, the antimicrobial efficiency of these three molecules is widely known and on the other hand, their collaborative key-role in ocular nerve functioning makes it remarkable to state here that their donors are supposed to act as a shield for both the infectious as well as the non-infectious eye defects.

Influence of acute mental stress on blood pressure, heart rate and heart rate variability in male medical students: An experimental study from tertiary care hospital, Nepal

Background: Medical students experience immense mental stress while understanding and retaining new terms, drug names and mechanisms and eventually generating a concept. Such stress, in long run, may affect their cardiovascular health. This can be assessed by heart rate variability, a reliable non-penetrating tool to determine the cardiac autonomic tone. Material and methods: Thirty healthy young male medical students of BPKIHS, Nepal of age 21.03 ± 1.73 years, and BMI 20.83 ± 2.07 kg/m2 were recruited for the present study. Their resting BP, HR, RR, and short-term heart rate variability (HRV) were recorded in sitting position. Each subject was given a mental stress for 5 min. Their BP, HR, and RR were recorded at 5th min of mental stress. HRV of 5 min was also recorded simultaneously during mental stress. Results: Mental stress increased SBP (p=0.001), DBP (p= 0.001), PR (p= 0.005) and RR (p= 0.042) in young male medical students. Time domain measures of HRV viz; RMSSD (p= 0.001), NN50 (p= 0.001) and PNN50 (p=0.001), which are markers of parasympathetic activity, were significantly decreased during mental stress. Conclusion: Acute mental stress increases BP and HR by withdrawing parasympathetic nervous control in young, healthy male medical students.

Is the Cerebellum Involved in the Nervous Control of the Immune System Function?

Background: According to the views of psychoneuroendocrinoimmunology, many interactions exist between nervous, endocrine and immune system the purpose of which is to achieve adaptive measures restoring an internal equilibrium (homeostasis) following stress conditions. The center where these interactions converge is the hypothalamus. This is a center of the autonomic nervous system that controls the visceral systems, including the immune system, through both the nervous and neuroendocrine mechanisms. The nervous mechanisms are based on nervous circuits that bidirectionally connect hypothalamic neurons and neurons of the sympathetic and parasympathetic system; the neuroendocrine mechanisms are based on the release by neurosecretory hypothalamic neurons of hormones that target the endocrine cells and on the feedback effects of the hormones secreted by these endocrine cells on the same hypothalamic neurons. Moreover, the hypothalamus is an important subcortical center of the limbic system that controls through nervous and neuroendocrine mechanisms the areas of the cerebral cortex where the psychic functions controlling mood, emotions, anxiety and instinctive behaviors take place. Accordingly, various studies conducted in the last decades have indicated that hypothalamic diseases may be associated with immune and/or psychic disorders. Objective: Various researches have reported that the hypothalamus is controlled by the cerebellum through a feedback nervous circuit, namely the hypothalamocerebellar circuit, which bi-directionally connects regions of the hypothalamus, including the immunoregulatory ones, and related regions of the cerebellum. An objective of the present review was to analyze the anatomical bases of the nervous and neuroendocrine mechanisms for the control of the immune system and, in particular, of the interaction between hypothalamus and cerebellum to achieve the immunoregulatory function. Conclusion: Since the hypothalamus represents the link through which the immune functions may influence the psychic functions and vice versa, the cerebellum, controlling several regions of the hypothalamus, could be considered as a primary player in the regulation of the multiple functional interactions postulated by psychoneuroendocrinoimmunology.

Syllable is a synchronization mechanism that makes human speech possible

Speech is a highly skilled motor activity that shares a core problem with other motor skills: how to reduce the massive degrees of freedom (DOF) to the extent that the central nervous control and learning of complex motor movements become possible. It is hypothesized in this paper that a key solution to the DOF problem is to eliminate most of the temporal degrees of freedom by synchronizing concurrent movements, and that this is done in speech through the syllable—a mechanism that synchronizes consonantal, vocalic and laryngeal gestures. Under this hypothesis, gestures are articulatory movements toward underlying targets; the onsets and offsets of the gestures are synchronized at the syllable edges, although more so at syllable onset than at the offset; and the realization of the synchronization is facilitated by sensorimotor feedback, especially tactile feedback, during consonant closures. This synchronization theory of the syllable also offers a comprehensive account of coarticulation, as it explicates how various coarticulation-related phenomena, including coarticulation resistance, locus, locus equation, diphone etc., are byproducts of syllable formation. It also provides a theoretical basis for understanding how suprasegmental events such as tone, intonation, phonation, etc. are aligned to segmental events in speech. It may also have implications for understanding vocal learning, speech disorders and motor control in general.