Autonomic and cardiovascular effects of pentobarbital anesthesia during trigeminal stimulation in cats.
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ABSTRACT:
SUBMITTER: Hanamoto H
PROVIDER: S-EPMC3412660 | biostudies-other | 2012 Mar
REPOSITORIES: biostudies-other
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Project description:Recent evidence indicates that transcranial ultrasound stimulation (TUS) modulates sensorimotor cortex excitability. However, no study has assessed possible TUS effects on the excitability of deeper brain areas, such as the brainstem. In this study, we investigated whether TUS delivered on the substantia nigra, superior colliculus, and nucleus raphe magnus modulates the excitability of trigeminal blink reflex, a reliable neurophysiological technique to assess brainstem functions in humans. The recovery cycle of the trigeminal blink reflex (interstimulus intervals of 250 and 500 ms) was tested before (T0), and 3 (T1) and 30 min (T2) after TUS. The effects of substantia nigra-TUS, superior colliculus-TUS, nucleus raphe magnus-TUS and sham-TUS were assessed in separate and randomized sessions. In the superior colliculus-TUS session, the conditioned R2 area increased at T1 compared with T0, while T2 and T0 values did not differ. Results were independent of the interstimulus intervals tested and were not related to trigeminal blink reflex baseline (T0) excitability. Conversely, the conditioned R2 area was comparable at T0, T1, and T2 in the nucleus raphe magnus-TUS and substantia nigra-TUS sessions. Our findings demonstrate that the excitability of brainstem circuits, as evaluated by testing the recovery cycle of the trigeminal blink reflex, can be increased by TUS. This result may reflect the modulation of inhibitory interneurons within the superior colliculus.
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Project description:We aimed to explore the effects of bilateral subthalamic nucleus stimulation and levodopa on cardiovascular autonomic function in Parkinson's disease. Twenty-six Parkinson's disease patients with bilateral subthalamic nucleus stimulation in a stable state were tested under stimulation off and dopaminergic medication off (OFF-OFF), stimulation on and dopaminergic medication off (ON-OFF), and stimulation on and medication (levodopa) on (ON-ON) conditions by recording continuously blood pressure, ECG, and respiration at rest, during metronomic deep breathing, and head-up tilt test. Thirteen patients were diagnosed as orthostatic hypotension by head-up tilt test. Baroreflex sensitivity and spectral analyses were performed by trigonometric regressive spectral analysis. Subthalamic nucleus stimulation and levodopa had multiple influences. (1) Systolic blood pressure during tilt-up was reduced by subthalamic nucleus stimulation, and then further by levodopa. (2) Subthalamic nucleus stimulation and levodopa had different effects on sympathetic and parasympathetic regulations in Parkinson's disease. (3) Levodopa decreased baroreflex sensitivity and RR interval only in the orthostatic hypotension group, and had opposite effects on the non-orthostatic hypotension group. These findings indicate that subthalamic nucleus stimulation and levodopa have different effects on cardiovascular autonomic function in Parkinson's disease, which are modulated by the presence of orthostatic hypotension as well.
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Project description:BackgroundSeveral disease processes of the colon and rectum, including constipation and incontinence, have been associated with abnormalities of the autonomic nervous system. However, the autonomic innervation to the colon and rectum are not fully understood. The aims of this study were to investigate the effect of stimulation of vagus nerves, pelvic nerves (PN) and hypogastric nerves (HGN) on colorectal motility in rats.MethodsFour strain gauge transducers were implanted on the proximal colon, mid colon, distal colon and rectum to record circular muscle contractions in rats. Electrical stimulation was administered to the efferent distal ends of the cervical vagus nerve, PN and HGN. Motility index (MI) was evaluated before and during stimulation.Key resultsElectrical stimulation (5-20 Hz) of the cervical vagus elicited significant contractions in the mid colon and distal colon, whereas less pronounced contractions were observed in the proximal colon. Pelvic nerves stimulation elicited significant contractions in the rectum as well as the mid colon and distal colon. Atropine treatment almost completely abolished the contractions induced by vagus nerve and PN stimulation. Hypogastric nerves stimulation caused relaxations in the rectum, mid colon and distal colon. The relaxations in response to HGN stimulation were abolished by propranolol.Conclusions & inferencesVagal innervation extends to the distal colon, while the PN has projections in the distribution of the rectum through the mid colon. This suggests a pattern of dual parasympathetic innervation in the left colon. Parasympathetic fibers regulate colorectal contractions via muscarinic receptors. The HGN mainly regulates colorectal relaxations via beta-adrenoceptors.
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Project description:Trigeminal autonomic cephalalgia (TAC) encompasses 4 unique primary headache types: cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms. They are grouped on the basis of their shared clinical features of unilateral headache of varying durations and ipsilateral cranial autonomic symptoms. The shared clinical features reflect the underlying activation of the trigeminal-autonomic reflex. The treatment for TACs has been limited and not specific to the underlying pathogenesis. There is a proportion of patients who are refractory or intolerant to the current standard medical treatment. From instrumental bench work research and neuroimaging studies, there are new therapeutic targets identified in TACs. Treatment has become more targeted and aimed towards the pathogenesis of the conditions. The therapeutic targets range from the macroscopic and structural level down to the molecular and receptor level. The structural targets for surgical and noninvasive neuromodulation include central neuromodulation targets: posterior hypothalamus and, high cervical nerves, and peripheral neuromodulation targets: occipital nerves, sphenopalatine ganglion, and vagus nerve. In this review, we will also discuss the neuropeptide and molecular targets, in particular, calcitonin gene-related peptide, somatostatin, transient receptor potential vanilloid-1 receptor, nitric oxide, melatonin, orexin, pituitary adenylate cyclase-activating polypeptide, and glutamate.
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Project description:PurposeElectronic cigarettes (ECs) are the fastest growing tobacco product in the USA, and ECs, like tobacco cigarettes (TCs), have effects on the cardiovascular autonomic nervous system, with clinical implications. The purpose of this review was to collect and synthesize available studies that have investigated the autonomic cardiovascular effects of EC use in humans. Special attention is paid to the acute and chronic effects of ECs, the relative contributions of the nicotine versus non-nicotine constituents in EC emissions and the relative effects of ECs compared to TCs.MethodsUsing the methodology described in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement, we conducted a literature search of the Ovid PubMed and Embase databases on 6 December 2019 using keywords in titles and abstracts of published literature. Acute (minutes to hours) and chronic (days or longer) changes in heart rate variability (HRV), heart rate (HR) and blood pressure (BP) were used as estimates of cardiovascular autonomic effects.ResultsNineteen studies were included in this systematic review, all of which used earlier generation EC devices. Acute EC vaping increased HR and BP less than acute TC smoking. Nicotine but not non-nicotine constituents in EC aerosol were responsible for the sympathoexcitatory effects. The results of chronic EC vaping studies were consistent with a chronic sympathoexcitatory effect as estimated by HRV, but this did not translate into chronic increases in HR or BP.ConclusionsElectronic cigarettes are sympathoexcitatory. Cardiac sympathoexcitatory effects are less when vaping using the earlier generation ECs than when smoking TCs. Additional studies of the latest pod-like EC devices, which deliver nicotine similarly to a TC, are necessary.
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Project description:IntroductionSpinal cord injury (SCI) may cause impairments of the motor, sensory, and autonomic nervous systems, which result in adverse changes in body composition and cardiovascular health. Functional electrical stimulation (FES) cycling may provide an effective alternative approach to perform exercise and improve cardiovascular health after SCI. Persons with an injury at or above T6 level are at high risk of developing a life-threatening complication of autonomic dysreflexia (AD).Case presentationTwo participants with motor-complete C6 SCI completed either 12 weeks of passive range of motion or surface neuromuscular electrical stimulation (NMES) resistance training, followed by 12 weeks of functional electrical stimulation (FES) lower extremity cycling for both participants. Systolic and diastolic blood pressure (BP) were measured to determine the effects of NMES-resistance training and FES-lower extremity cycling during rest and exercise.DiscussionThe difference between mean value of BP during FES-lower extremity cycling exercise and resting BP averaged for 24 sessions was smaller for participant A (31.25?mmHg for systolic BP and 10.44?mmHg for diastolic BP), who received NMES-resistance training, as compared with participant B (58.62?mmHg for systolic BP and 35.07?mmHg for diastolic BP). The results of these case reports suggest that 12 weeks of NMES-resistance training preceding FES-lower extremity cycling may attenuate the development of AD after SCI. Risk of AD, triggered by noxious stimuli, may be dampened with FES-lower extremity cycling training in persons with SCI.
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Project description: Not available
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Project description:This study reports the case of an acoustic shock injury (ASI), which did not result in a significant hearing loss, but was followed by manifold chronic symptoms both within (tinnitus, otalgia, tingling in the ear, tension in the ear, and red tympanum) and outside the ears (blocked nose, pain in the neck/temporal region). We suggest that these symptoms may result from a loop involving injury to middle ear muscles, peripheral inflammatory processes, activation and sensitization of the trigeminal nerve, the autonomic nervous system, and central feedbacks. The pathophysiology of this ASI is reminiscent of that observed in post-traumatic trigeminal-autonomic cephalalgia. This framework opens new and promising perspectives on the understanding and medical management of ASI.
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Project description:Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and has minimal risk for extrapyramidal symptoms. Therapeutic benefits, however, are accompanied by a myriad of cardiometabolic side-effects. The specific reasons for clozapine's high propensity to cause adverse cardiometabolic events remain unknown, but it is believed that autonomic dysfunction may play a role in many of these. Objective: This systematic review summarizes the literature on autonomic dysfunction and related cardiovascular side effects associated with clozapine treatment. Method: A search of the EMBASE, MEDLINE, and EBM Cochrane databases was conducted using the search terms antipsychotic agents, antipsychotic drug*, antipsychotic*, schizophrenia, schizophren*, psychos*, psychotic*, mental ill*, mental disorder*, neuroleptic*, cardiovascular*, cardiovascular diseases, clozapine*, clozaril*, autonomic*, sympathetic*, catecholamine*, norepinephrine, noradrenaline, epinephrine, adrenaline. Results: The search yielded 37 studies that were reviewed, of which only 16 studies have used interventions to manage cardiovascular side effects. Side effects reported in the studies include myocarditis, orthostatic hypotension and tachycardia. These were attributed to sympathetic hyperactivity, decreased vagal contribution, blockade of cholinergic and adrenergic receptors, reduced heart rate variability and elevated catecholamines with clozapine use. Autonomic neuropathy was identified by monitoring blood pressure and heart rate changes in response to stimuli and by spectral analysis of heart rate variability. Metoprolol, lorazepam, atenolol, propranolol, amlodipine, vasopressin and norepinephrine infusion were used to treat tachycardia and fluctuations in blood pressure, yet results were limited to case reports. Conclusion: The results indicate there is a lack of clinical studies investigating autonomic dysfunction and a limited use of interventions to manage cardiovascular side effects associated with clozapine. As there is often no alternative treatment for refractory schizophrenia, the current review highlights the need for better designed studies, use of autonomic tests for prevention of cardiovascular disease and development of novel interventions for clozapine-induced side effects.
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Project description:BackgroundGastroesophageal reflux (GER) is poorly characterized in anesthetized cats, but can cause aspiration pneumonia, esophagitis, and esophageal stricture formation.ObjectiveTo determine whether pre-anesthetic orally administered omeprazole increases gastric and esophageal pH and increases serum gastrin concentrations in anesthetized cats, and to determine the prevalence of GER using combined multichannel impedance and pH monitoring.AnimalsTwenty-seven healthy cats undergoing elective dental procedures.MethodsProspective, double-masked, placebo-controlled, randomized clinical trial. Cats were randomized to receive 2 PO doses of omeprazole (1.45-2.20 mg/kg) or an empty gelatin capsule placebo 18-24 hours and 4 hours before anesthetic induction. Blood for measurement of serum gastrin concentration was collected during anesthetic induction. An esophageal pH/impedance catheter was utilized to continuously measure esophageal pH and detect GER throughout anesthesia.ResultsMean gastric pH in the cats that received omeprazole was 7.2 ± 0.4 (range, 6.6-7.8) and was significantly higher than the pH in cats that received the placebo 2.8 ± 1.0 (range, 1.3-4.1; P < .001). Omeprazole administration was not associated with a significant increase in serum gastrin concentration (P = .616). Nine of 27 cats (33.3%) had ?1 episode of GER during anesthesia.Conclusions and clinical relevancePre-anesthetic administration of 2 PO doses of omeprazole at a dosage of 1.45-2.20 mg/kg in cats was associated with a significant increase in gastric and esophageal pH within 24 hours, but was not associated with a significant increase in serum gastrin concentration. Prevalence of reflux events in cats during anesthesia was similar to that of dogs during anesthesia.
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