1.
Gastric accommodation: Physiology, diagnostic modalities, clinical relevance, and therapies.
Febo-Rodriguez, L, Chumpitazi, BP, Sher, AC, Shulman, RJ
Neurogastroenterology and motility. 2021;(12):e14213
Abstract
BACKGROUND Gastric accommodation is an essential gastric motor function which occurs following ingestion of a meal. Impaired gastric fundic accommodation (IFA) is associated with dyspeptic symptoms. Gastric accommodation is mediated by the vagal pathway with several important physiologic factors such as duodenal nutrient feedback playing a significant role. IFA has been described as a pathophysiologic factor in several gastrointestinal disorders including functional dyspepsia, diabetic gastropathy, post-Nissen fundoplication, postsurgical gastrectomy, and rumination syndrome. Modalities for gastric accommodation assessment include gastric barostat, intragastric meal distribution via scintigraphy, drinking tests (eg, water load), SPECT, MRI, 2D and 3D ultrasound, and intragastric high-resolution manometry. Several treatment options including sumatriptan, buspirone, tandospirone, ondansetron, and acotiamide may improve symptoms by increasing post-meal gastric volume. PURPOSE Our aim is to provide an overview of the physiology, diagnostic modalities, and therapies for IFA. A literature search was conducted on PubMed, Google Scholar, and other sources to identify relevant studies available until December 2020. Gastric accommodation is an important gastric motor function which if impaired, is associated with several upper gastrointestinal disorders. There are an increasing number of gastric accommodation testing modalities; however, each has facets which warrant consideration. Evidence regarding potentially effective therapies for IFA is growing.
2.
Spastic movement disorder: impaired reflex function and altered muscle mechanics.
Dietz, V, Sinkjaer, T
The Lancet. Neurology. 2007;(8):725-33
Abstract
In clinical practice, signs of exaggerated tendon tap reflexes associated with muscle hypertonia are generally thought to be responsible for spastic movement disorders. Most antispastic treatments are, therefore, directed at the reduction of reflex activity. In recent years, however, researchers have noticed a discrepancy between spasticity as measured in the clinic and functional spastic movement disorders, which is primarily due to the different roles of reflexes in passive and active states, respectively. We now know that central motor lesions are associated with loss of supraspinal drive and defective use of afferent input with impaired behaviour of short-latency and long-latency reflexes. These changes lead to paresis and maladaptation of the movement pattern. Secondary changes in mechanical muscle fibre, collagen tissue, and tendon properties (eg, loss of sarcomeres, subclinical contractures) result in spastic muscle tone, which in part compensates for paresis and allows functional movements on a simpler level of organisation. Antispastic drugs can accentuate paresis and therefore should be applied with caution in mobile patients.
3.
Modulation operated by the sympathetic nervous system on jaw reflexes and masticatory movement.
Passatore, M, Roatta, S
Archives of oral biology. 2007;(4):343-6
Abstract
The sympathetic nervous system (SNS), that is activated under condition of physical, psychological and psychosocial stress, affects force production and fatigability of muscles by controlling both muscle blood flow and the intracellular contractile mechanism. In addition SNS may affect motor function by modulating afferent activity from muscle spindles that are highly concentrated in jaw-closing muscles. Possible implications of these actions on masticatory function and myofascial pain are discussed.
4.
[New insights into neural mechanisms controlling the micturition reflex].
Yoshimura, N
Nihon yakurigaku zasshi. Folia pharmacologica Japonica. 2003;(5):290-8
Abstract
The functions of the lower urinary tract, to store and periodically release urine, are dependent on the activity of smooth and striated muscles in the bladder, urethra, and external urethral sphincter. This activity is in turn controlled by neural circuits in the brain, spinal cord, and peripheral ganglia. During urine storage, the outlet is closed and the bladder smooth muscle is quiescent. When bladder volume reaches the micturition threshold, activation of a micturition center in the dorsolateral pons (the pontine micturition center) induces a bladder contraction and a reciprocal relaxation of the urethra, leading to bladder emptying. During voiding, sacral parasympathetic (pelvic) nerves provide an excitatory input (cholinergic and purinergic) to the bladder and inhibitory input (nitrergic) to the urethra. The brain rostral to the pons (diencephalon and cerebral cortex) is also involved in excitatory and inhibitory regulation of the micturition reflex. Various transmitters including dopamine, serotonin, norepinephrine, GABA, excitatory and inhibitory amino acids, opioids, acetylcholine, and neuropeptides are implicated in the modulation of the micturition reflex in the central nervous system. Therefore, injury or diseases of the nervous system, as well as drugs and disorders of the peripheral organs, can produce bladder and urethral dysfunctions such as urinary frequency, urgency and incontinence, or inefficient bladder emptying.