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Results for “SELF STIMULATION”

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At least 325 records · Page 18Linked to original sources

PubMed1980

5HT blockade and the stimulant effects of D- and L-amphetamine: no interaction in self-stimulation of prefrontal cortex, hypothalamus, or dorsal tegmentum. unexpected lethality in hippocampal sites.

We investigated the role of serotonin in the differential stimulatory effects of D- and L-amphetamine (1.0 mg/kg) on locomotor activity and on self-stimulation (SS) in rats. The serotonin antagonist methysergide (12.5 mg/kg) had no effects alone on activity or on SS. Methysergide enhanced the strong locomotor stimulatory effects of D-amphetamine and the weaker effects of L-amphetamine. D-amphetamine facilitated SS more strongly than L- in hypothalamic, dorsal tegmental, hippocampal and medial prefrontal cortical sites, but the effect of D-amphetamine was much weaker in prefrontal cortex than in other sites. Methysergide did not alter the effects of D- or L-amphetamine in any site except the hippocampus. Here, methysergide plus L-amphetamine suppressed SS; methysergide plus D-amphetamine suppressed SS in some rats and greatly increased it in others. When SS was facilitated by D-amphetamine plus methysergide, the combination was lethal. The possibility that lethality was due to adrenal crisis is discussed.

Amphetamine↗

PubMed1974

Vagotomy: effect on electrically elicited eating and self-stimulation in the lateral hypothalamus.

A subdiaphragmatic vagotomy markedly inhibits eating and self-stimulation produced in rats by lateral hypothalamic stimulation. The stomach is known to be affected by hypothalamic stimulation via the vagus, and afferents from the stomach can influence the hypothalamus via the same nerve. Consequently, this result suggests that eating and self-stimulation may be partly controlled by hypothalamic influences on the stomach which, in turn, affects hypothalamic sensitivity.

Animals↗

PubMed1986

[The role of ACTH(5-8) and beta-MSH(5-8) fragments in the organization of the self-stimulation reaction].

The experiments on rats have shown that intraperitoneal administration of ACTH5-8 fragments in a dose of 40 ng per kg altered considerably the character of self-stimulation reaction and the behaviour of rats. Searching activity and self-stimulation reaction were intensified, with the latter characterized by the onset of aversive components, that disappeared 24 hours later. Activation depended on the site of stimulation. Two phases of activity were noted (the first 0.5-1 h and the second 4.5-6 h after ACTH5-8 injection). beta-MSH5-8 fragment, when injected intraperitoneally in a dose of 20 ng per kg, had no effect on self-stimulation reaction and the behaviour of animals.

Adrenocorticotropic Hormone↗

PubMed1981

The tetracyclic antidepressant mianserin: evaluation of its blockade of presynaptic alpha-adrenoceptors in a self-stimulation model using clonidine.

It has been suggested that the tetracyclic antidepressant mianserin may be an antagonist at inhibitory presynaptic alpha-adrenoceptors. If mianserin exerted a selective antagonist effect it should produce effects that are essentially opposite to those of a selective agonist such as clonidine. This hypothesis was investigated in a shuttle-box self-stimulation model previously shown to be sensitive to alpha-adrenergic drugs. In this model a presynaptic alpha-adrenoceptor antagonist would be expected to enhance self-stimulation and to reverse the inhibitory effects of clonidine. Mianserin (2.5-4.0 mg/kg) did not enhance self-stimulation, but instead produced a selective inhibition of reward. Further, mianserin did not reverse the inhibitory effects of clonidine on self-stimulation. These data suggest that if mianserin is an antagonist of the presynaptic alpha-adrenoceptors it is not a selective antagonist. It is possible that the presynaptic alpha-adrenoceptor antagonism may be effects on postsynaptic alpha-adrenoceptors and/or on a presynaptic noradrenaline reuptake mechanism.

Adrenergic alpha-Antagonists↗

PubMed1984

Site-specific naloxone blockade of brain self-stimulation duration.

Moderate doses of naloxone (1, 5, 10 mg/kg) did not reduce response rate measured by the initiation of intracranial self-stimulation bursts to the medial forebrain bundle or central gray, at several current intensities (30, 60, or 90 microA). Raising current intensity rates and duration of lever pressing at both sites. Naloxone produced a dose dependent reduction in self-selected current duration at both sites averaged over intensity. However, naloxone completely blocked the effect of intensity only at the gray site. In contrast to research showing effects of only high naloxone doses (e.g., 40 mg/kg) on self-stimulation at opiate-rich and opiate-poor receptor sites, this study indicates that endogenous opiates and opiate receptor mechanisms interact with aversive properties to modify central gray self-stimulation.

Animals↗

PubMed1979

[Change in the cholesterol and triglyceride content in the blood in self-stimulation and avoidance reactions].

The changes in the blood serum cholesterol and triglyceride content were studied or rabbits of both sexes during reactions of self-stimulation and avoidance. Self-stimulation was accompanied by a significant decrease in the blood serum cholesterol and triglyceride content. During the reaction of avoidance the character of the cholesterol changes varied. The reaction of avoidance of the "agression" type was accompanied by elevated blood serum cholesterol content, whereas the reaction of the "fear" type was associated with a decrease in its content. The maximal changes in the cholesterol and triglyceride content as compared to the initial level were observed in all types of the reactions 15--30 minutes following stimulation.

Animals↗

PubMed1980

Intracranial self-stimulation in mice using a modified hole-board task: effects of d-amphetamine.

Mice implanted with stimulating electrodes in the lateral hypothalamus demonstrated reliable self-stimulation rates when given the opportunity to break a photobeam in a modified hole-board task. Self-stimulation rates were enhanced by low dosages of d-amphetamine but were depressed by high dosages. The dose-dependent effects of amphetamine could not be accounted for by changes in exploratory hole-board activity and were discussed in terms of an interaction between the rewarding properties of electrical brain stimulation and the reinforcing properties of amphetamine administration.

Animals↗

PubMed1984

Development of species identification in ducklings: XII. Ineffectiveness of auditory self-stimulation in wood ducklings (Aix sponsa).

A previous study revealed that wood ducklings vocalize copiously when in auditory isolation. However, such self-stimulation appeared to be ineffective in maintaining their preference for the characteristically descending frequency-modulated (FM) notes of the wood duck maternal call. Only isolated birds that had been exposed to a recording of descending sib calls showed the normal preference for descending maternal notes in a choice test with descending and ascending maternal calls. In this study, the actual vocalizations of stimulated and unstimulated wood ducklings were examined in order to explore the possibility that there is a difference in the kind and/or amount of auditory self-stimulation in the two groups (e.g., the stimulated birds might produce more descending calls). Although the stimulated birds produced more ascending notes than the unstimulated birds, no differences were found in the overall vocal behavior, vocal reactivity, or specific kinds of frequency modulation produced by the birds that preferred the descending maternal call and the other birds that responded in the choice test. The absence of a difference in vocal production between the birds that preferred the descending call and the other responding birds supports the previous conclusion that self-stimulation apparently plays no role in the development or maintenance of the species-typical perceptual preference for the descending FM notes of the wood duck maternal call.

Animals↗

PubMed1983

Unilaterally activated systems in rats self-stimulating at sites in the medial forebrain bundle, medial prefrontal cortex, or locus coeruleus.

Rats with electrodes in either the posterior medial forebrain bundle (MFB), the anterior MFB, the medial prefrontal cortex, or the locus coeruleus self-stimulated during a 45 min period following the injection of [14C]2-deoxyglucose. They were then sacrificed and their brains prepared for autoradiography. The autoradiographs were analyzed for unilaterally activated neural systems, using a computerized image analyzing system to compare the darkness of neural structures on the stimulated side with the darkness of the same structures on the unstimulated side. There was extensive overlap in the neural structures unilaterally activated by stimulation in the anterior and posterior MFB; but there was no overlap between the structures activated by MFB stimulation and the structures activated by stimulation at either of the extradiencephalic sites; nor did the forebrain, diencephalic, and midbrain sites have any readily apparent bilateral effects in common. If there is a substrate common to MFB self-stimulation and extradiencephalic self-stimulation, its activation is not revealed by 2-deoxyglucose autoradiography.

Animals↗

PubMedDate not supplied

Ethanol and current thresholds for brain self-stimulation in the lateral hypothalamus of the rat.

Two groups of animals were implanted with stimulating electrodes in the lateral hypothalamus for intracranial self-stimulation (ICSS). Following surgery these animals were trained in the auto-titration, brain self-stimulation procedure which measured both the rate of responding and the reinforcement threshold for electrical stimulation. When behavior was stable, one group was given saline or ethanol (0.1-1.7 g/kg) administered intraperitoneally (IP) either 15 or 60 min before testing. The other group was given saline or ethanol (1.0-4.5 g/kg) administered intragastrically (IG) 15 or 60 min before testing. With IP administration, there was a graded decrease in lever-pressing at 15 min but the effect was less obvious at 60 min. There were no changes in threshold except at the highest dose when behavior was disrupted. With IG administration, a reduction in the rate of responding occurred at 15 min only. No changes in thresholds were observed at any dose level or injection-test interval. Thus, administration of ethanol either by the IP or IG route did not affect the reinforcement thresholds for ICSS in the lateral hypothalamus, and these results contrasted with those of other drugs of abuse such as amphetamine or morphine.

Animals↗

PubMedDate not supplied

[The effect of 2- and 3-component hyperbaric breathing mixtures on the self-stimulation reaction and on the skeletal muscle electromyogram of rabbits].

The effects of two- and three-component normoxic mixtures on self-stimulation and total bioelectrical activity of the skeletal muscles were evaluated in six test runs with 37 male rabbits. The increased partial pressures of He and N2 are found to affect differently intensity of self-stimulation which is enhanced in an O2-N2 environment and suppressed in that one consisting of He-O2. The He-N2-O2 mixture in which N2 amounts to 6% under pressure of 40 kgs/cm2 does not cause significant changes in self-stimulation as compared to that exposed by He-O2 breathing mixture. In contrast, trimix breathing (N2 amounts to 6%) under the same pressure did not result in an elevation in amplitude of muscular electric activity observed when used hyperbaric He-O2 breathing mixture. The experimental results may be indicative of an involvement of different mechanisms in genesis of the nervous syndrome of high pressure as well as of the fact that adding of N2 to He-O2 mixture does not allow this pathologic state to be completely prevented.

Animals↗

PubMedDate not supplied

Cortical and ventral tegmental systems exert opposing influences on self-stimulation from the prefrontal cortex.

Intracranial self-stimulation (ICSS) was obtained from 3 areas of anteromedial cortex: the prelimbic area (Brodman's area 32), the anterior cingulate area and the posterior cingulate area. Electrical stimulation in the prelimbic and anterior cingulate areas also produces a behavioral inhibition which is most pronounced at anterior sites (i.e. prelimbic) and declines at increasingly more posterior sites. It was found that the acquisition of responding for ICSS and the magnitude of amphetamine's facilitation of ICSS were inversely related to the degree of behavioral inhibition. These data and the ability of amphetamine to reverse prefrontal stimulation-induced inhibition suggest an important interaction between the prefrontal cortex and the mesolimbic dopamine systems in the control of goal-directed behavior. A model involving cortical suppression of mesolimbic dopamine function is discussed.

Animals↗

PubMedDate not supplied

[Relation between the dynamics of the extinction process and the initial rate of hypothalamic self-stimulation in the rabbit].

In experiments on rabbits with electrodes chronically implanted in the lateral hypothalamus, dynamics was studied of extinction of self-stimulation reaction as a result of cancellation of intracerebral reinforcement. General dynamics of extinction of the unreinforced instrumental actions and behavioural manifestations of orienting-investigating reaction were revealed. It was found, that in 30% of rabbits, the orienting reaction appearing as a result of "discordance" between expected and actual afferentation is attended by a species-specific form of behaviour, expressed in the form of hind paws synergic strokes against the floor. It is suggested that these strokes may be a somatic expression of a negative emotional state of animals during self-stimulation extinction. The comparison of extinction dynamics with the level of self-stimulation background frequency showed a relative independence of the strength of drive towards getting positive emotions on motivational effects created by electric stimulation of the reinforcing brain structures.

Animals↗

PubMed2000

Patterns of dopamine overflow in mouse nucleus accumbens during intracranial self-stimulation.

Dopamine (DA) overflow in the mouse nucleus accumbens during intracranial self-stimulation (ICSS) of the median forebrain bundle was estimated by chronoamperometry with removable carbon fibre electrodes. The specificity of the voltammetric signal was confirmed pharmacologically. The parameters of stimulation (50 Hz, 0.5 s train length) allowed us to obtain measurable DA release and to maintain ICSS. Continuous (CR) and fixed-ratio (FR8) schedule of reinforcement showed differing correspondence of the patterns of DA release with the patterns of stimulation/nose-poking. The CR schedule induced a high rate nose-poking and tonic increase in dopamine overflow, which became decreased following the first periods of self-stimulations. The FR schedule induced stable peaks of DA overflow during the entire period of ICSS. We conclude that the availability of a readily-releasable pool of DA in presynaptic terminals determined the pattern of dopamine overflow in the nucleus accumbens during ICSS in mice.

Animals↗

PubMed1981

"Conflict" situation based on intracranial self-stimulation behavior and the effect of benzodiazepines.

Based on lateral hypothalamic self-stimulation behavior of the rat in a Skinner box, a "conflict" situation was established by combining foot shock punishment with brain stimulation. Diazepam (10-20 mg/kg, PO) caused a marked increase in the lever pressing response in the punished period without affecting the unpunished response. Bromazepam (10--20 mg/kg PO) also caused an increase in the lever pressing response in the punished period and a decrease of the punished response. These results indicate that a "conflict" situation based on self-stimulation behavior is useful for the evaluation of antianxiety action.

Animals↗

PubMed1980

Effects of Lilly 110140 (flouxetine) on self-stimulation behavior in the dorsal and ventral regions of the lateral hypothalamus in the mouse.

The effects of Lilly 110141 (fluoxetine) injected IP on self-stimulation behavior triggered in the dorsal and ventral regions of the lateral hypothalamus were studied in C57BL/6 mice strain. Lilly 110140 inhibits serotonin reuptake. It depresses dorsal self-stimulation at a low dose (5 mg/kg) and improves ventral sel-stimulation at a high dose (20 mg/kg). The changes brought about by the injection of the 5 mg/kg dose support the proposed inhibitory role of serotonin on self-stimulation and also suggest that the fibers communicating with certain serotonergic neurons are localized primarily in the dorsal region of the lateral hypothalamus.

Animals↗

PubMed1988

The interactive effects of cocaine and imipramine on self-stimulation train-duration thresholds.

The present experiment examined the ability of the tricyclic antidepressant imipramine to influence cocaine's effect on intracranial self-stimulation. Following a predrug, saline injection period, cocaine hydrochloride (10, 20 or 30 mg/kg) was injected (IP) in 19 rats implanted with ventral tegmental area electrodes. Cocaine treatment uniformly decreased self-stimulation train-duration thresholds. In the next phase, the subjects were divided into two groups. One group received cocaine (as in the previous phase) and the other received cocaine plus imipramine (10 mg/kg, IP). Imipramine doubled cocaine's effect on self-stimulation train-duration thresholds. In addition, several other effects of cocaine (e.g., bradycardia, rear-limb dyskinesia) were potentiated by imipramine treatment. The results suggest that care must be exercised when treating cocaine abuse with tricyclic antidepressants since coadministration of these drugs intensifies cocaine's effects.

Animals↗

PubMed1979

Enhancement of self-stimulation behavior in rats and monkeys after chronic neuroleptic treatment: evidence for mesolimbic supersensitivity.

The effect of chronic neuroleptic drug treatment on self-stimulation of the mesolimbic dopamine system was tested. Rats with electrodes implanted into the ventral tegmental nucleus (A10 cell body area) were treated with haloperidol for three weeks. Afterwards, the rats showed a 35% increase in self-stimulation rate, as compared to pre-drug control rates. This increase persisted for three weeks after drug withdrawal before returning to baseline rates. Rats treated for three weeks with the atypical neuroleptic, clozapine, also showed an increase, the duration and magnitude of which was similar to that seen in the haloperidol group. In addition, four rhesus monkeys with electrodes in the nucleus accumbens (one of the terminal projection areas of the A10 mesolimbic dopamine system) were given a three week treatment with haloperidol, after which all animals showed a significant, long-lasting decrease in self-stimulation threshold, as measured by a rate-independent reward paradigm. Taken together, these results suggest the induction of receptor supersensitivity in the mesolimbic dopamine system by long-term treatment with neuroleptic drugs.

Animals↗