Biomaterial Database

Involvement of the ventral tegmental area opiate receptors in self-stimulation elicited from the ventral pallidum. 1998

G Panagis, and A Kastellakis, and C Spyraki

Department of Basic Sciences, School of Medicine, University of Crete, Greece.

Enkephalinergic and dopaminergic mechanisms have been implicated in the electrical self-stimulation (SS) behavior. The present set of experiments investigated the role of opioid receptors within DA-innervated brain regions (nucleus accumbens and ventral tegmental area) in the ventral pallidum self-stimulation (VP-SS). Forty-one rats used in this study were implanted with a monopolar moveable stimulating electrode in the VP. A rate-frequency curve-shift method was applied to determine the reward (threshold) and motor functions (asymptotic rate) of self stimulation elicited from the VP. One group received systemic treatment of graded doses (vehicle; 1.25; 2.50 mg/kg) of morphine injected IP, 60 min before behavioural testing. The results showed a tendency for increased threshold of VP-SS and of the asymptotic rate of responding. Three additional groups were implanted with guide cannulae in the nucleus accumbens (NAC), the ventral tegmental area (VTA) or dorsally to the VTA and received microinjections of morphine (vehicle: 1.25; 2.50; 5.0; 10.0 microg/0.5 microl per side). Central injections of morphine higher than 1.25 microg/side into the VTA were associated with a significant reduction in VP-SS thresholds, indicating a potentiative effect on reward. Microinjections of morphine either into the NAC or into the dorsal tegmentum did not produce significant alterations on thresholds or responding of VP-SS. In order to investigate the extent to which the VTA-NAC dopamine projection was involved in the SS behavior elicited from the ventral pallidum, we tested SS in animals that suffered NAC 6-hydroxydopamine (6-OHDA) lesions. Rats suffering NAC dopamine depletion along with their corresponding controls showed similar levels of thresholds and responding to the ones exhibited prior to the lesion, revealing that NAC dopamine is not necessary to maintain VP-SS. The results suggest that stimulation of opioid receptor in the VTA increases the rewarding efficacy of VP-SS. This effect might be due to the modulation of VTA-DA neurons projecting to the VP rather than to the NAC.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009020	Morphine	The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.	Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D009294	Narcotics	Agents that induce NARCOSIS. Narcotics include agents that cause somnolence or induced sleep (STUPOR); natural or synthetic derivatives of OPIUM or MORPHINE or any substance that has such effects. They are potent inducers of ANALGESIA and OPIOID-RELATED DISORDERS.	Analgesics, Narcotic,Narcotic Analgesics,Narcotic,Narcotic Effect,Narcotic Effects,Effect, Narcotic,Effects, Narcotic
D009714	Nucleus Accumbens	Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.	Accumbens Nucleus,Nucleus Accumbens Septi,Accumbens Septi, Nucleus,Accumbens Septus, Nucleus,Accumbens, Nucleus,Nucleus Accumbens Septus,Nucleus, Accumbens,Septi, Nucleus Accumbens,Septus, Nucleus Accumbens
D011957	Receptors, Opioid	Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.	Endorphin Receptors,Enkephalin Receptors,Narcotic Receptors,Opioid Receptors,Receptors, Endorphin,Receptors, Enkephalin,Receptors, Narcotic,Receptors, Opiate,Endorphin Receptor,Enkephalin Receptor,Normorphine Receptors,Opiate Receptor,Opiate Receptors,Opioid Receptor,Receptors, Normorphine,Receptors, beta-Endorphin,beta-Endorphin Receptor,Receptor, Endorphin,Receptor, Enkephalin,Receptor, Opiate,Receptor, Opioid,Receptor, beta-Endorphin,Receptors, beta Endorphin,beta Endorphin Receptor,beta-Endorphin Receptors
D004298	Dopamine	One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.	Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D005917	Globus Pallidus	The representation of the phylogenetically oldest part of the corpus striatum called the paleostriatum. It forms the smaller, more medial part of the lentiform nucleus.	Paleostriatum,Pallidum,Pallidums
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012201	Reward	An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.	Rewards
D012653	Self Stimulation	The act or process of inducing or increasing the level of arousal in oneself. It can be observed in various situations; for example, infants who are understimulated may explore their surroundings or babble to themselves.(https://dictionary.apa.org/self-stimulation accessed 12/30/2020)	ICSS Intracranial Self-Stimulation,Intracranial Self Stimulation,Self-Stimulation,Intracranial Self Stimulations,Self Stimulation, Intracranial,Self Stimulations,Self Stimulations, Intracranial,Self-Stimulations,Stimulation, Self,Stimulations, Self