Ocular Autonomic Nervous System: An Update from Anatomy to Physiological Functions

The autonomic nervous system (ANS) confers neural control of the entire body, mainly through the sympathetic and parasympathetic nerves. Several studies have observed that the physiological functions of the eye (pupil size, lens accommodation, ocular circulation, and intraocular pressure regulation) are precisely regulated by the ANS. Almost all parts of the eye have autonomic innervation for the regulation of local homeostasis through synergy and antagonism. With the advent of new research methods, novel anatomical characteristics and numerous physiological processes have been elucidated. Herein, we summarize the anatomical and physiological functions of the ANS in the eye within the context of its intrinsic connections. This review provides novel insights into ocular studies.

Autonomic Nervous System

The autonomic nervous system is involved in many important unconscious body functions. It is critical for maintaining the internal environment in response to changes in the external environment. The autonomic nervous system consists of peripheral components (sympathetic and parasympathetic nerves and ganglia) and central components (ventrolateral medulla, nucleus ambiguus, nucleus of the solitary tract, periaqueductal gray, anterior cingulate gyrus, insular cortex, amygdala, and hypothalamus). This chapter briefly reviews the anatomy and functional components of the autonomic nervous system and several anatomical clinical correlations.

A semi-randomized study determining the psychological and physical effects of three types of eye masks on adult women

Background: Warm compresses are one of the nursing techniques clinically used to improve patients’ comfort and promote the treatment efficacy. Here the effects of eye masks (EM), heated eye masks (HEM), and aroma-scented heated eye masks (AHEM) and their potential as a nursing technique to provide comfort were studied.Methods: Participants in this study were 42 healthcare professionals (female, 20–60 years of age), who voluntarily consented to participate. They participated in all three interventions with EM, HEM, and AHEM at an interval of at least 1 week between interventions. Indicators used were low frequency to high frequency ratio (LF/HF), blood flow, axillary temperature, pulse rate, blood pressure, the salivary α-amylase activity (SAA), and the Profile of Mood States Second Edition (POMS).Results: Of 42 participants in total, 32 were included in the analysis. Their mean age was 46.8 years. The blood flow and axillary temperature values significantly increased and the LF/HF values and the pulse rates significantly decreased after the use of EM, HEM, or AHEM. The POMS Total Mood Disturbance (TMD) score and scores for six POMS subscales significantly decreased after the use of EM, HEM, or AHEM.Comparisons among the three groups showed differences in LF/HF. Scores for subscales of POMS also differed among the three groups.Conclusions: These results suggest that the use of EM, HEM, or AHEM intervention is safe with no major body burden. Parasympathetic nerves may be dominant after the EM, HEM, or AHEM interventions The TMD score improved after the EM, HEM, or AHEM intervention. The data suggest that the AHEM use is particularly effective in alleviating depression, dejection, and confusion after the intervention. These findings indicates that the EM, HEM, or AHEM use holds potential as a nursing technique to provide comfort.Trial registration: UMIN Clinical Trials Registry (UMIN000018409Trial registration number: UMIN-CTR R000021207Date of registration: 07/24/2015

Sophisticated regulation of micturition: review of basic neurourology

The neurological regulation of the lower urinary tract can be viewed separately from the perspective of sensory neurons and motor neurons. First, in the receptors of the bladder and urethra of sensory nerves, sensations are transmitted through the periaqueductal gray matter of the midbrain to the cerebral cortex, and the cerebrum goes through the process of decision-making. Motor neurons are divided into upper motor neurons (UMNs) and lower motor neurons (LMNs). UMNs coordinate storage and micturition in the brain stem so that synergic voiding can occur. LMNs facilitate muscle contractions in the spinal cord. The muscles involved in urinary storage and micturition are innervated by the somatic branches of sympathetic, parasympathetic, and peripheral nerves. Sympathetic nerves are responsible for contractions of urethral smooth muscles, while parasympathetic nerves originate from S2–S4 and are in charge of contractions of the bladder muscle. Somatic nerves originate from the motor neurons in Onuf’s nucleus, which is a specific part of somatic nerves. In this review, we will investigate the structures of the nervous systems related to the lower urinary tract and the regulatory system of innervation for the urinary storage and micturition and discuss the clinical significance and future prospects of neurourological research.

Inosine as a Tool to Understand and Treat Central Nervous System Disorders: A Neglected Actor?

Since the 1970s, when ATP was identified as a co-transmitter in sympathetic and parasympathetic nerves, it and its active metabolite adenosine have been considered relevant signaling molecules in biological and pathological processes in the central nervous system (CNS). Meanwhile, inosine, a naturally occurring purine nucleoside formed by adenosine breakdown, was considered an inert adenosine metabolite and remained a neglected actor on the purinergic signaling scene in the CNS. However, this scenario began to change in the 1980s. In the last four decades, an extensive group of shreds of evidence has supported the importance of mediated effects by inosine in the CNS. Also, inosine was identified as a natural trigger of adenosine receptors. This evidence has shed light on the therapeutic potential of inosine on disease processes involved in neurological and psychiatric disorders. Here, we highlight the clinical and preclinical studies investigating the involvement of inosine in chronic pain, schizophrenia, epilepsy, depression, anxiety, and in neural regeneration and neurodegenerative diseases, such as Parkinson and Alzheimer. Thus, we hope that this review will strengthen the knowledge and stimulate more studies about the effects promoted by inosine in neurological and psychiatric disorders.

The effect of music therapy on children with autism as a therapeutic intervention

Objective: The global incidence of autism has rised up. It can appear the importance of interventions and family struggles, because music is attractive for children we can use it as an effective intervention. The goal of this article is a review of the ASD children problems and interventions and the music effects for treating children with Autism Spectrum Disorder (ASD). Finally, since music is always accessible and the human body utilizes it on a daily basis, we can use music as a complementary method in occupational therapy. Materials & Methods: Comprehensive electronic search of keywords "music therapy", "autism interventions" and "vagus nerve stimulation" was done in international electronic databases such as PubMed, Scopus, Google Scholar and Google Books between 2000 and 2021. In the first part of the search, based on the considered keywords, 30,446 articles were obtained. After reviewing the abstracts of articles, 30,405 articles were discarded due to lack of entry criteria, and finally 41 articles were selected. Among these, 30 articles focused on autism and its interventions and another 11 articles focused on the vagus nerve. Results: children with autism have lots of problems in different aspects and communicate with them is not like normal children. One best way to break this barrier is music. According to Physics, music is placed in energy spectrum as one part of sounds and volumes, which can affect on our body energy. On the other side the rhythmical and compositionality feature of music reinforce this consequence. Due to these features, music is more popular and we can utilize it for children with autism, who don't have enough eye contact and communication. We often use music in our daily lives, for example, from ringing the doorbell to using the phone or waiting in the elevator to reach the desired floor and etc. it is one common and available supplementary way that we can use it for treating beside the other methods. The music plays an important role in activation of Parasympathetic Nervous System via the vagus nerve stimulation. The vagus nerve is a tenth nerve of twelve pairs cerebral nerves. The tenth nerve is one of the most important nerves which originates from the brain and is responsible for innervating face, thorax, abdomen and etc. It is a motor sensory nerve. The vagus nerve is also involved in the Parasympathetic Nervous System. The parasympathetic nerves have a great effect on the relaxation of the body. Vagus nerve has two sensory ganglia that transmits sensory impulses: the superior and the inferior ganglia, by which we can affect on parasympathetic nerves for improvement. Generally these ganglions innervates different part of body such as: ear (where the most stimulations happen in this place) , larynx, heart, pulmonary system, abdomen and abdominal viscera. Because of this innervation vagus nerve stimulation can change the activity of pulmonary system, heart, abdomen, intestine and etc. and contributes to relaxation. The music stimulates the vagus receptors of the ear. Conclusion: Since music is an accessible and attractive resource, it can be used as a complementary method along with medication and other methods, due to which the connection with the child with autism is established and under the shadow of relaxation, learning and more concentration is provided. Keywords: Music Therapy, autism interventions, Vagus Nerve Stimulation

Influence of Ectopic Beats on Heart Rate Variability Analysis

The analysis of heart rate variability (HRV) plays a dominant role in the study of physiological signal variability. HRV reflects the information of the adjustment of sympathetic and parasympathetic nerves on the cardiovascular system and, thus, is widely used to evaluate the functional status of the cardiovascular system. Ectopic beats may affect the analysis of HRV. However, the quantitative relationship between the burden of ectopic beats and HRV indices, including entropy measures, has not yet been investigated in depth. In this work, we analyzed the effects of different numbers of ectopic beats on several widely accepted HRV parameters in time-domain (SDNN), frequency-domain (LF/HF), as well as non-linear features (SampEn and Pt-SampEn (physical threshold-based SampEn)). The results showed that all four indices were influenced by ectopic beats, and the degree of influence was roughly increased with the increase of the number of ectopic beats. Ectopic beats had the greatest impact on the frequency domain index LF/HF, whereas the Pt-SampEn was minimally accepted by ectopic beats. These results also indicated that, compared with the other three indices, Pt-SampEn had better robustness for ectopic beats.

Lateral Habenula Regulates Cardiovascular Autonomic Responses via the Serotonergic System in Rats

The lateral habenula (LHb) plays essential roles in behavioral responses to stressful events. Stress is tightly linked to autonomic responses such as cardiovascular responses, yet how the LHb regulates these responses is not well understood. To address this issue, we electrically stimulated the LHb in rats, measured its effects on heart rate (HR) and mean arterial pressure (MAP), and investigated the neural circuits that mediate these LHb-induced cardiovascular responses via the autonomic nervous system. We observed that stimulation of the LHb induced bradycardia and pressor responses, whereas stimulation of the adjacent areas changed neither the HR nor the MAP. Bilateral vagotomy and administration of a muscarinic receptor antagonist suppressed the LHb stimulation effect on the HR but not on the MAP, whereas administration of a β-adrenoceptor antagonist partly attenuated the effect on the MAP but not on the HR. Thus, the LHb-induced cardiovascular responses of the HR and the MAP were likely caused by activations of the cardiac parasympathetic nerves and the cardiovascular sympathetic nerves, respectively. Furthermore, administration of a non-selective 5-HT receptor antagonist significantly attenuated the LHb stimulation effects on both the MAP and the HR. A 5-HT2 receptor antagonist also attenuated the LHb stimulation effects. A low dose of a 5-HT1A receptor antagonist enhanced the LHb stimulation effects, but a high dose of the drug attenuated them. 5-HT1B and 5-HT1D receptor antagonists as well as a 5-HT7 receptor antagonist did not affect the LHb stimulation effects. Taken together, our findings suggest that the LHb regulates autonomic cardiovascular responses at least partly through the serotonergic system, particularly via the 5-HT1A and 5-HT2 receptors.

Cranial hyperthermia resulting from decreased parotid gland salivation induced by ischemic degeneration of glossopharyngeal network in subarachnoid hemorrhage

Objective: We speculated that subarachnoid hemorrhage (SAH) induces ischemic lesions in the cranial parasympathetic nerves, which may decrease saliva secretion and lead to hyperthermia. We tested this hypothesis by examining histologic features of parotid glands and glossopharyngeal nerves (GPNs) in a rabbit model of SAH. Material and Methods: Rabbits (n = 25) were divided into control (n = 5), sham (n = 5), and SAH (n = 15) groups. Animals in the sham and SAH groups were examined over a 3-week period before sacrifice. Salivation score (SC) was determined by measuring the mean wetted area of an orally inserted cotton ball. Sections of parotid glands and intracranial and intraparotideal branches of the GPNs were stained with hematoxylin and eosin and SAH-induced damage was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling of apoptotic cells. Specimens were stereologically examined to determine saliva-filled total vesicle volume (TVV) per cubic meter; vasospasm index (VSI) based on wall/lumen ratio of parotid glands arteries, and degenerated neuron density (DND) of glossopharyngeal ganglia. Results: The mean oral temperature was 36.9°C. In the control group, mean values were as follows: SC, 46±8 mm2; DND, 19±4/mm3; VSI, 1.065±0.049; and TVV, (780±1187) × 106/µm3. In the sham group, mean values were as follows: SC, 31±6 mm2; DND, 98±23/mm3; VSI, 1.67±0.32; and TVV, (617±110) × 106/µm3. In the low hyperthermia SAH group, mean values were as follows: SC, 16±5 mm2; DND, 1520±261/mm3; VSI, 2.12±0.21, and TVV, (314±98) × 106/µm3. In the high hypothermia SAH group, mean values were as follows: SC, 9±2 mm2; DND, 3210±912/mm3; VSI, 3.18±0.30; and TVV, (432±99) × 106/µm3. Conclusions: Decreased salivary secretion due to secretory gland atrophy originated from ischemia-induced GPN network degeneration at the brainstem, which may be responsible for cranial hyperthermia following SAH.