Cardiovascular, impllent and sensory reactions of various specializations athletes on vestibular irritation

It is marked in the article that the average value of heart chronotropic reaction of athletes to vestibular irritation from different positions of a head and duration of sensory reactions are inversely related to exercise saturation of every kind of sport by angular accelerations. Severity of the systolic blood pressure reaction of various specializations athletes does not differ. Strength and frequency of hand movements of athletes increase on the background of the rotational load, and accuracy of the given efforts declines, but these changes are not related to their specialization. In the controls these rates are reduced, though their accuracy of effort is much greater than athlete's accuracy efforts.     

Motor and autonomic asymmetries in athletes with different specializations and nonathletes: Communication 2

Data on changes in the electrical activity of paravertebral muscles, autonomic indices, and the lateral organization profile arising during training in subjects with different patterns of physical exercise are presented.     

Triggering and gating of motor responses by sensory stimulation: behavioural selection in Xenopus embryos.

Neural mechanisms underlying selection of motor responses are largely unknown in vertebrates. This study shows that in immobilized Xenopus embryos, brief mechanical or electrical stimulation of the trunk skin can trigger sustained fictive swimming, whereas sustained pressure or repetitive electrical stimulation can evoke fictive struggling. These two rhythmic motor patterns are distinct: alternating single motor root spikes propagate from head to tail during swimming; alternating motor root bursts propagate from tail to head during struggling. As both motor patterns can be evoked in embryos with the CNS transected caudal to the cranial roots, the sensory pathway responsible must have direct access to the spinal cord. Rohon-Beard sensory neurons provide the only such pathway known. They respond appropriately to brief stimuli applied to the trunk skin, and also to repetitive electrical stimuli and sustained pressure. The results suggest that Rohon-Beard sensory neurons can both trigger sustained swimming and 'gate in' struggling motor patterns, and thus effect behavioural selection according to their pattern of activity.     

Cardiac responses to sensory stimulation in the adult tobacco budworm moth, Heliothis virescens

Electrocardiogram recordings were performed on intact Heliothis virescens moths using Ag-AgCl electrodes positioned on the body cuticular surface. Regular heart activity and its changes in response to mechanical and olfactory stimulations were analysed. Moths were also tested in their anemotactic orientation in response to olfactory stimulation. Results show that regular cardiac activity in Heliothis is cyclical and consists of the alternation of a high and a low spike-frequency period. This activity pattern is strongly influenced by sensory stimulation. Both mechanical stimulations at various intensities and olfactory stimulations with sex pheromone and 1-hexanol evoked tachycardiac effects when applied during low spike-frequency cardiac activity. In contrast, they did not affect high spike-frequency cardiac activity. It is concluded that the cardiac response in Heliothis is an effective indicator of sensory reception. It would therefore appear to represent a valid tool for testing insect reactivity. Accepted: 30 August 1997     

Integrative responses of neurons in nucleus tractus solitarius to visceral afferent stimulation and vestibular stimulation in vertical planes

Anatomical studies have demonstrated that the vestibular nuclei project to nucleus tractus solitarius (NTS), but little is known about the effects of vestibular inputs on NTS neuronal activity. Furthermore, lesions of NTS abolish vomiting elicited by a variety of different triggering mechanisms, including vestibular stimulation, suggesting that emetic inputs may converge on the same NTS neurons. As such, an emetic stimulus that activates gastrointestinal (GI) receptors could alter the responses of NTS neurons to vestibular inputs. In the present study, we examined in decerebrate cats the responses of NTS neurons to rotations of the body in vertical planes before and after the intragastric administration of the emetic compound copper sulfate. The activity of more than one-third of NTS neurons was modulated by vertical vestibular stimulation, with most of the responsive cells having their firing rate altered by rotations in the head-up or head-down directions. These responses were aligned with head position in space, as opposed to the velocity of head movements. The activity of NTS neurons with baroreceptor, pulmonary, and GI inputs could be modulated by vertical plane rotations. However, injection of copper sulfate into the stomach did not alter the responses to vestibular stimulation of NTS neurons that received GI inputs, suggesting that the stimuli did not have additive effects. These findings show that the detection and processing of visceral inputs by NTS neurons can be altered in accordance with the direction of ongoing movements.     

Morphological and sensory specializations of five New Zealand flatfish species, in relation to feeding behaviour

The morphology of the feeding apparatus and sensory systems of flatfish species Rhombosolea plebeia (Richardson, 1843), Rhombosolea leporina Günther, 1862, Peltorhamphus novaezeelandiae Günther, 1862, Pelotretis flavilatus Waite, 1911 (f. Pleuronectidae) and Arnoglossus scapha (Forster, in Bloch & Schneider, 1801) (f. Bothidae) are described. The four pleuronectid species have asymmetric jaws and non-toothed gill rakers typical of benthic-feeding flatfish, while the bothid has symmetric jaws and toothed gill rakers typical of midwater-feeding flatfish. R. plebeia, R. leporina and P. novaezeelandiae have extensive external taste bud systems which facilitate non-visual prey location. External tastebuds are lacking in P. flavilatus and A. scapha ; however, these two species have relatively large, prominent eyes which facilitate visual prey location. The lateral line is well-developed in all five species, but R. plebeia, R. leporina and particularly P. novaezeelandiae have additional free neuromasts on their blind sides, which probably assist in prey location.
The feeding habits of these flatfish species closely reflect their morphological and sensory specializations. A detailed feeding study in Wellington Harbour, New Zealand showed that R. plebeia, R. leporina and P. novaezeelandiae have closely overlapping diets consisting of largely sedentary or inactive invertebrates living in the bottom sediments. In contrast, P. flavilatus and A. scapha have specialized diets of one or two species only. While the latter two species differ in that P. flavilatus is a benthic feeder and A. scapha is pelagic feeder, both are visual feeders and therefore more specialist than the other three species.     

Cardiovascular responses to melanocortin 4-receptor stimulation in conscious unrestrained normotensive rats

In the present studies, we used a non-selective melanocortin MC3/4 receptor agonist (HP228) and a novel selective melanocortin MC4 receptor (MC4-R) agonist (MK-cpd1) to study the cardiovascular, temperature, locomotor and feeding responses to melanocortin receptor stimulation in comparison to sibutramine in rats instrumented with a telemetry transmitter. Moreover, norepinephrine turnover rates in heart and brown adipose tissue were determined. HP228 (1, 3 and 10mg/kg, i.p.) reduced 24h food intake dose-dependently and increased heart rate and mean arterial pressure (maximal differences: +60+/-8beats/min and +8+/-1mmHg, means+/-S.E.M., p<0.001 and p<0.01, respectively). After 10mg/kg HP228 showed a three-fold increase in norepinephrine turnover in the heart. The selective MC4-R agonist MK-cpd1 tended to decrease 24h food intake only at the highest dose tested (10mg/kg, i.p., p=0.06) and increased both heart rate (+17+/-4 and +22+/-5beats/min at 3 and 10mg/kg, p<0.01) and mean arterial pressure (+4+/-1mmHg at 10mg/kg, p<0.05). Sibutramine reduced food intake at all doses tested (1, 3 and 10mg/kg, i.p.). It did not change mean arterial pressure significantly, and increased heart rate only at the highest dose tested (+36+/-6beats/min, p<0.05). If also observed in humans, the pharmacological profile of MC4-R agonists would not offer a significant therapeutic advantage over currently used appetite suppressants such as sibutramine.