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Results for “Escape Reaction”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Effect of a change in brain monoamine levels on reproduction of an elaborated escape reaction in rats].

An escape reaction was elaborated in Wistar rats in a shuttle box to shocks delivered to the animal's foot in a time stereotype. Single administrations of serotonin precursor--5-Hydroxytryptophane (10 mg/kg) and of catecholamine inhibitor--M-tyrosine (100 mg/kg) had a facilitating effect on this reaction. The animals' behaviour became regulated; this was manifested in a shortening of latencies. Catecholamine precursor d,l-DOPA (35 mg/kg) and serotonin inhibitor p-Chlorophenilalanine (320 mg/kg) worsened the rats' adaptive behaviour in the experimental situation enhancing their fuss movements. The latencies of the escape reactions became longer. The data presented point to a reciprocal--conjugate interaction of serotonin- and noradrenergic brain systems as well as to an antistress serotonin effect on behaviour.

5-Hydroxytryptophan↗
PubMed1992

Effect of NaCl addition on nanosecond O2 escaping reaction of myoglobin: evidences for the transition of myoglobin dynamic structure at 20 degrees C.

We studied the nanosecond (ns) geminate O2 escape reaction from the protein interior of myoglobin (Mb) to the solvent phase in the temperature range of 5-40 degrees C containing 0-0.1 M NaCl. In the flash photolysis experiments, we found that both the rate constant, kout, and its Arrhenius plot changed upon the variation of the NaCl concentration. In particular, it was noteworthy that the Arrhenius plot of kout dramatically changed in its slope, keeping the break at 20 degrees C, upon the addition of NaCl, indicating that the thermodynamic parameters such as an enthalpy of activation (delta H not equal to) and an entropy of activation (delta S not equal to) are different between above and below 20 degrees C, and that they are further altered upon the NaCl addition to the sample solution. From these results, we suggested that the Mb dynamic structure in the ns geminate O2 escape reaction is sensitively regulated by the interaction of the protein surface and the salt. The present study also showed that an inconsistency of the Arrhenius plot of kout between Chatfield et al. ((1990) J. Am. Chem. Soc. 112, 4680-4687) and us ((1990) J. Biol. Chem. 265, 18823-18828) is probably due to the difference in the solution condition.

Myoglobin↗
PubMed1991

Impaired escape reaction from noxious and nonnoxious heat in rats treated with the selective noradrenergic neurotoxin DSP-4.

The escape reaction, as an indicator of behavioral thermoregulation, was studied in rats pretreated with the selective noradrenergic neurotoxin DSP-4. The animals were kept for 30 min in a heated floor (42, 44, 46, 48 and 50 degrees C) cage containing a wooden platform placed at a height of 12 cm, which enabled the rats to escape from the warm floor. The latency of escape and the time spent on the platform were recorded. The performance of DSP-4-treated rats was significantly inferior to that of the control rats at all tested temperatures. These findings indicate a general function of the central noradrenergic neurons in defense alarm reactions, including a significant role in heat defense behavior.

Animals↗
PubMed1991

[Enhancement of the resistance of the escape reaction to ethanol after substance P].

An ability of substance P (30 micrograms/kg intravenously) to prevent deleterious effects of ethanol (E) (0.5 g/kg intravenously) on central mechanisms of escape reaction elicited by threshold electrical stimulation of the ventromedial hypothalamus was investigated in chronic experiments upon rabbits. Substance P was found to prevent E effects on excitability of the ventromedial hypothalamus (VMH) and on facilitatory influences of the midbrain reticular formation on this emotional centre which were observed in intact animals. Inhibitory effects of the dorsal hippocampus on the VMH could not be evaluated due to its alterations in response to previous substance P administration. The authors suggest that substance P can be considered to be a possible endogenous factor to increase a tolerance of emotional behavioural reactions of an organism to alcohol.

Animals↗
PubMed1992

Cholinergic transmission at the first synapse of the circuit mediating the crayfish lateral giant escape reaction.

1. The chemical synapses between mechanoreceptor neurons and first-order interneurons in the lateral giant (LG) neuron escape circuit of the crayfish have plastic properties, some of which are believed to be the basis for behavioral habituation and sensitization. In this investigation pharmacological experiments were conducted to assess the role of cholinergic synaptic transmission in this pathway. 2. Arterial perfusion of the cholinergic agonist carbachol produced increased activity of many abdominal nerve cord units, including an identified first-order interneuron (interneuron A) in the LG circuit. A general increase in activity of interneurons in this circuit in the presence of certain cholinergic agonists was inferred from an increase in the frequency of occurrence of spontaneous excitatory postsynaptic potentials (EPSPs) recorded in the LG. 3. Cholinergic antagonists reduced the amplitude of spontaneous and evoked sensory neuron-to-interneuron A EPSPs and decreased the disynaptic (via 1st-order interneurons) component of evoked EPSPs in the LG. These effects indicate that postsynaptic cholinergic receptors are utilized in mechanosensory synaptic transmission to the first-order interneurons of this circuit. The relative potencies of the blockers tested (mecamylamine > picrotoxin >>> curare > atropine) suggest that the receptors on the interneurons belong to a previously characterized class of crustacean cholinergic receptors that resemble the ganglionic nicotinic subtype of vertebrates. 4. Nicotinic agonists (carbachol, tetramethylammonium hydroxide, 1,1-dimethyl-4-phenyl-piperazium iodide) produced depolarizing (decreased input resistance) responses on the LG neuron itself. These responses persisted during blockade of chemical transmission by cobalt. The presence of cholinergic receptors on the LG, a cell in which all known inputs mediating sensory excitation are electrical, is discussed. 5. Application of muscarinic agonists (pilocarpine, oxotremorine) resulted in a long-lasting reduction of the evoked sensory neuron-to-interneuron A EPSP and the disynaptic component of the evoked EPSP in the LG. No effects on the membrane potential or input resistance of the interneurons were detected. It is proposed that presynaptic receptors with a muscarinic profile are present on mechanosensory neurons and that these receptors mediate a reduction of transmitter release.

Acetylcholine↗
PubMed1979

Salivary cooling, escape reaction and heat pain in capsaicin-desensitized rats.

Salivary thermolytic mechanisms (weight of salivary glands, effect of desalivation on water intake and body temperature, grooming activity) as well as escape behaviour and reaction to heat pain were studied in capsaicin-desensitized and control rats exposed to various warm ambient temperatures. Body temperature of the desensitized rats increased more than the controls' at all the ambient temperatures studied (32, 34 and 36 degrees C); however, significant differences in the mechanism of salivary cooling were obtained only at 34 and 36 degrees C. Central impairment of saliva spreading in desensitized rats seems evident. Complete surgical desalivation did not increase hyperthermia of control and desensitized animals in warm environments. Therefore other mechanisms, primarily vasodilatatory, must also be involved in the rat's thermolytic normal response. Although desensitized rats did not show a tendency to escape from the warm environment their response to heat pain was normal. In conclusion, it is suggested that heat perception in desensitized animals is impaired; however, the existence of some capsaicin-insensitive thermolytic mechanisms (prone extension of the body) cannot be excluded.

Animals↗
PubMedDate not supplied

[Sensitivity of Nereis virens polychaetes to mechanical oscillations in water].

Food and escape reactions of Nereis virens to oscillations of a ball 2 mm in diameter in water have been studied. These antagonistic reactions differ significantly by the range of ball oscillations which evoked them. The range from 10 to 30 Hz appeared to be optimal for food reaction, and the range above 40 Hz -- for escape reaction. Worms are able to detect a ball from a distance of 12--13 mm at optimal oscillation frequency 30 Hz. Possible receptor mechanisms providing these types of reaction are discussed.

Animals↗
PubMedDate not supplied

[The role of the lateral and medial hypothalamus in reproducing food and escape instrumental reactions].

In experiments on two dogs it has been found that testing electric stimulation of the lateral hypothalamus reproduces instrumental movement in case of elaborated alimentary instrumental conditioned reflexes (CR) to a tone and does not reproduce it at elaborated acid-defensive instrumental CR. Under testing electric stimulation of the medial hypothalamus the instrumental movement practically is not reproduced neither in alimentary nor in defensive situation. Appearance of instrumental movement at LH electro-stimulation in alimentary situation is connected with activation of backward conditioned connection from motivation "alimentary" LH centre to representation of this movement in the motor cortex.

Acoustic Stimulation↗
PubMed1977

Spinal trigeminal tractotomy and nociceptive reactions evoked by tooth pulp stimulation in the cat.

The effect of transection of the descending root of the spinal trigeminal tract on nociceptive and aversive reactions evoked by stimulation of the tooth pulp nerve was studied in cats. The transection was performed 1-1.5 mm caudally to the obex. 1. The nociceptive reaction, characterized by wide opening of the jaw, dorsiflexion and rotation of the head and by signs of affective behaviour, remained unchanged after transection of the descending root of the trigeminal nerve (n = 6). 2. The instrumental escape reaction was elaborated in three cats before transection of the descending root of the trigeminal nerve and in three cats after transection. The escape reaction was retained after transection of the descending root and the speed of learning to escape the tooth pulp stimulation did not significantly differ in these two groups of animals. 3. It is to be concluded that the transection of the descending root of the spinal trigeminal tract in the cat does not result in dental analgesia.

Animals↗
PubMed1992

[Beta-adrenoblockers in the reorganizing of the food center of the hypothalamus under the influence of substance P].

An ability of substance P (15 nmol intracerebroventricularly) to transform functional properties of the hypothalamic feeding center manifested in escape reaction in response to threshold electrical stimulation of this motivation center in rabbits. Beta-adrenergic antagonists inderal and obsidan (0.25, 0.5 mg, respectively) injected intravenously were found to restore feeding elicited by electrostimulation of the hypothalamic feeding center. However, escape reaction, elicited from the feeding center under substance P was found unchanged after intravenous administration of 0.25 mg kalipsol. The data obtained suggested an important role of beta-adrenergic mechanisms in substance P transformation of the functional properties of the hypothalamic feeding centre.

Adrenergic beta-Antagonists↗
PubMed1979

Peripheral stimulation in mice induces short-duration analgesia preventable by naloxone.

Peripheral stimulation was applied to mice by mild caudal electrostimulation, by mechanical pressure or by footshock for 30 sec, before testing on a 52 degrees C hot plate. Reaction times to paw lick and to escape from the hot plate were recorded. Analgesia could be elicited and measured by these procedures. It was of short duration, declining in a minute, and was antagonized by low doses of naloxone. The analgesia measured by the escape reaction time could be elicited after multiple caudal electrostimulation as well as in morphine-tolerant mice, and it could still be reversed by naloxone. An opioid link is thus involved in this phenomenon, which also supports the notion of more than one opioid pathway existing in the brain. The short period of analgesic cover afforded in the face of noxious stimuli would permit aversive action to be taken in nature and thus might represent the prime functional role of enkephalins in the brain.

Analgesia↗
PubMed1978

Evaluation of functional degeneration of the amazon-ant Polyergus rufescens Latr. under an influence of socially parasitic way of life.

In certain, infrequently occurring, favorable circumstances the ants P. rufescens can display patterns of behavior which seem to be disappearing as a result of their parasitic way of life: the ability to food themselves, independently though ineffectively, elements of the offspring-protection behavior, transporting of nestmates, escape reaction. Similar events reinforce the infrequently used, latent reflexes, preventing their complete extinction. It is supposed that the characteristic in conventional parasitism disappearance of certain elements of behavior is inhibited by a social way of life. It may also be true of other, non-insect communities.

Animals↗