Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042963 (vomiting)
 31,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using squirrel monkeys as experimental subjects, we reexamined the disputed role of the area postrema (AP) in motion-induced vomiting. After anesthetization, the obex and rhomboid fossa were exposed surgically, and the AP was ablated by thermal coagulation using either a battery cautery or a CO2 microsurgical laser. Sham operations were performed on another sample of monkeys. Two or more weeks after surgery, all animals were given 10 daily 2-hour horizontal rotations at 30 rpm. Every monkey in both the lesions and sham samples vomited on two or more test days. While the vomiting characteristics were modified following ablation of AP, its function is not indispensible for the development of motion sickness in horizontally-rotated squirrel monkeys.
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PMID:Motion-induced sickness following bilateral ablation of area postrema in squirrel monkeys. 377 20

Squirrel monkeys, susceptible to the vestibular-visual conflict sickness in pitch (with frank vomiting), were subjected to repeated exposure to pitch conflict in various modes and in a randomly mixed order (30 min daily, for 10 consecutive days). Immediately after the training, a significant decline in susceptibility was found, represented by reduced vomiting rates, reduced sickness scores, reduced salivation and improved regularity of vertical oculomotor responses. Susceptibility at the pre-training level returned when the test was repeated 10 days later. Temporary suppression of pitch conflict sickness susceptibility indicates the possibility of training crew members prior to their space flight missions to control the space motion sickness, particularly vomiting.
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PMID:Change in susceptibility to vestibular-visual conflict sickness in monkeys by repeated exposure. 378 43

Space sickness symptoms were observed by 4 specially trained observers on Spacelab-1. Three reported persistent symptoms, and vomited repeatedly during the first and/or second day of flight. Head movements on all axes were provocative, particularly in pitch and roll. Head acceleration data recorded from 2 symptomatic crewmen showed that after several hours of physical activity in orbit, symptoms appeared, and thereafter both crewmen were compelled to limit head movements. Firm body contact with motionless surfaces helped alleviate symptoms. When crewmembers floated into unfamiliar body orientations in the cabin, inherent ambiguities in static visual orientation cues sometimes produced spatial reorientation episodes which were also provocative. Symptoms largely resembled those of other forms of prolonged motion sickness, superimposed upon other symptoms attributable to fluid shift. All 4 eventually used anti-motion sickness drugs. When they did, vomiting frequency was reduced. By the 4th day, symptoms subsided, and head accelerations again increased in magnitude and variability. Sickness intensity in orbit was not predicted by statistically concordant results of 6 acute preflight susceptibility tests. However, results from a longer duration preflight prism goggles test showed an apparent correlation. All subjects were asymptomatic making head movements in parabolic flight 4 days after the mission, but not 1 year later. Overall, results support the view that space sickness is a motion sickness.
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PMID:M.I.T./Canadian vestibular experiments on the Spacelab-1 mission: 4. Space motion sickness: symptoms, stimuli, and predictability. 380 76

Orally administered metoclopramide (REGLAN) at doses of 10 or 20 mg, 75 min prior to either stressful linear acceleration (parabolic flight) or cross-coupled accelerative semicircular canal stimulation in a rotating chair was evaluated for its ability to prevent emesis or nausea II, respectively. Although metoclopramide is an effective antiemetic agent that enhances gastric emptying and prevents cancer chemotherapy-induced emesis, we were unable to demonstrate any significant (p less than 0.05) effects of this drug on motion sickness.
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PMID:Failure of metoclopramide to control emesis or nausea due to stressful angular or linear acceleration. 382 87

The emetic chemoreceptor trigger zone (CTZ), located in the area postrema of the medulla oblongata, is generally believed to be indispensable for the vomiting in motion sickness and, by extrapolation, also in space sickness. Accordingly, it has been postulated that a "motion vomiting substance" is secreted into the cerebrospinal fluid in the emetic process. Furthermore, certain therapeutic measures against motion sickness are aimed at preventing the presumed chemical stimulation of the CTZ. This concept originated from laboratory experiments in which ablation of the area postrema protected some dogs and monkeys against motion-induced vomiting. More recent experiments, however, showed that verified lesions of the area postrema were not effective in preventing motion sickness in cats. It appears that an indispensable unidentified element close to but separate from the area postrema was fortuitously destroyed in the earlier experiments. The overall evidence leads to the conclusion that the area postrema is not essential for motion-induced vomiting. Therefore, no functional basis exists for the postulation of a motion vomiting substance, and it is irrational for the treatment of motion sickness to seek pharmacologic blocking agents that act at the CTZ.
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PMID:A misconception of motion sickness leads to false therapeutic expectations. 391 2

Motion sickness, a multisymptom disorder characterized by abnormal gastrointestinal motility and emesis, can be induced by vestibular effects on the sympathetic portion of the autonomic nervous system. However, the vestibular-autonomic pathways are unknown. As a first step in the analysis, we identified the locus of preganglionic sympathetic neurons (PSNs) and dorsal root afferent ganglionic neurons (DRGs) which supply sympathetic innervation to major portions of the gastrointestinal tract in the rabbit. Retrograde labeling of neurons was obtained by application of horseradish peroxidase (HRP) to the cut end of the greater splanchnic nerve. Labeled PSNs were found, ipsilaterally, within the T1 to T11 spinal cord segments, with the highest density of neurons in T6. Most PSNs were located within the intermediolateral column (IML), but a significant portion also occurred within the lateral funiculus (LF), the intercalated region (IC) and the central autonomic area (CA). The proportion of labeling between the four regions depended on the spinal cord segment. In the midthoracic levels, the distribution of labeled neurons was denser in the IML and LF, and in the caudal thoracic segments, the majority were localized in the IC and CA. Labeled cells in these four areas varied morphologically from large fusiform neurons in the IC to small fusiform neurons in the LF, small stellate neurons in the CA, and medium-size stellate neurons in the IML. The DRGs were labeled in thoracic segments T1 to T12, with the majority between T5 and T11. These labeled DRG somata of the greater splanchnic nerve were smaller in comparison with unlabeled ones.
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PMID:Sympathetic preganglionic efferent and afferent neurons mediated by the greater splanchnic nerve in rabbit. 396 18

Under a variety of experimental conditions, nonrestrained adult male squirrel monkeys were subjected to continuous rotation in the horizontal plane at 33 rpm. Severity of motion-induced sickness was quantified by measuring latencies of three responses associated with sickness. Per- and postrotational nystagmus was recorded from a subsample of monkeys with permanent recording electrodes implanted in the bony orbits. Incidence of sickness depended on the time limits of stimulation imposed, and it occurred in a maximum of about 90 per cent of test sessions if rotation was continued for two hours. When subjected to ten once-per-day rotation sessions, only a few monkeys showed evidence of developing transient habituation of onset of motion sickness. Mean frequency of emetic episodes, however, declined over the latter half of the rotation series. Restricting visual cues by blindfolding the monkeys prevented most subjects from vomiting.
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PMID:Experimental motion sickness induced in squirrel monkeys by continuous off-axis horizontal rotation. 397 7

Central cholinergic pathways modulate both the perception of excessive motion stimuli and the expression of motion sickness symptoms, such as nausea and vomiting. Specific brainstem areas which mediate motion-induced emesis include the area postrema (AP), vagal nuclear complex (VNC), reticular formation (RF) at the site of the vomiting center, and the vestibular complex (VC). In this report, histological studies indicated the cellular organization of brainstem structures mediating emesis was similar in bovine and squirrel monkey brain. The objective of this study was to characterize biochemical and pharmacological properties of muscarinic cholinergic receptors assayed by 3H-QNB binding in these regions of bovine brainstem. Scatchard analyses of specific 3H-QNB binding showed an uneven distribution of muscarinic receptors, with high densities of sites in VNC and AP, intermediate levels in RF and lowest receptor concentrations in VC. Dissociation constants for 3H-QNB, measured in saturation and kinetic experiments, were similar in all brainstem regions. The pharmacological potency of cholinergic agonists and antagonists was the same as reported for muscarinic receptors labeled in other brain areas or peripheral organs. Several drugs which potently inhibited 3H-QNB binding in bovine brainstem also exhibited antiemetic activity in a squirrel monkey model of motion-induced emesis. The antimotion sickness effects of these drugs may be due, in part, to their antagonism of muscarinic receptors in brainstem areas regulating emesis.
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PMID:Muscarinic cholinergic receptors in area postrema and brainstem areas regulating emesis. 399 61

The adequate management of cancer chemotherapy side effects continues to be a challenging problem. There is considerable variability in the side effects experienced by different patients to the same chemotherapeutic drugs. Clinical observations and previous findings of neuropathways between the vestibular system and vomiting center prompted this case-control study of whether susceptibility to motion sickness is a determinant of the type and magnitude of the side effects resulting from cancer chemotherapy. Eighty-three of 486 (17%) consecutive patients who were receiving chemotherapeutic drugs as their only treatment for histologically confirmed cancer reported previous motion sickness. Seventy-seven of these study patients were matched to cancer patient controls without previous motion sickness by sex, age, type and dose of chemotherapeutic drug received, and antiemetic medication. Study patients reported significantly greater nausea and vomiting (P less than 0.05), significantly more side effects (P less than 0.05), and a pattern of more frequent, severe, and longer-lasting nausea and vomiting than controls. Susceptibility to motion sickness appears to be a determinant of the side effects of cancer chemotherapy that may prove useful as a clinical marker of those patients who may require more intensive side effect management.
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PMID:The effect of a susceptibility to motion sickness on the side effects of cancer chemotherapy. 399 85

We conducted a double-blind, placebo-controlled study to evaluate the efficacy and tolerability of transdermal scopolamine in the prevention of motion sickness (MS) aboard a frigate during 7 days of continuously moderate or heavy seas. Forty-nine healthy sailors with a previous history of MS were randomly assigned to receive a transdermal therapeutic system of scopolamine (TTS-S) or transdermal placebo (TD-P). Patches were placed behind the ears at least 4 hours before departure and were removed 72 hours later. Subjects were observed on days 1 to 4 and 6. In the TTS-S group, both subjective feeling of MS and the incidence of nausea were reduced during the first 2 days. Because of adaptation, differences in signs and symptoms of MS between subjects receiving TTS-S and TD-P disappeared after the second day. During the first 3 days, vomiting occurred less often in the TTS-S group. On day 6, 3 days after removal of the patch, vomiting occurred in 23% of the TTS-S group, probably due to delay in adaptation, but none of the subjects in the TD-P group vomited. Concentration was not adversely influenced, since the ability to work increased in the TTS-S group. During prolonged continuous exposure to heavy and moderate seas, 2.5 cm2 TTS-S discs proved to be efficacious in preventing MS, with xerostomia as a tolerable side effect and no significant ocular side effects.
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PMID:Influence of transdermal scopolamine on motion sickness during 7 days' exposure to heavy seas. 402 25


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