The effects of the active ingredient of Cannabis, Delta9-tetrahydrocannabinol (Delta9-THC), and of the highly addictive drug heroin on in vivo dopamine transmission in the nucleus accumbens were compared in Sprague-Dawley rats by brain microdialysis. Delta9-THC and heroin increased extracellular dopamine concentrations selectively in the shell of the nucleus accumbens; these effects were mimick...

We investigated the effect of chronic administration of morphine on noxious stimulus-induced antinociception (NSIA) produced by intraplantar capsaicin injection. In the untreated (naive) rat, we previously found that NSIA depends on activation of dopamine, nicotinic acetylcholine, and mu- and delta-opioid receptors in nucleus accumbens. Rats chronically implanted with subcutaneous morphine pell...

In the present study, interactive effects of D1 and D2 dopamine receptors antagonists and different periods of lithium pretreatment on morphine dependence in mice have been investigated. This study was designed to investigate whether the hypothesis that lithium and dopaminergic mechanisms via their effects on phosphoinositide pathways and calcium flux could influence morphine withdrawal respons...

Corpus striatum neurons acutely dissociated from the brains of young adult rats had membrane surfaces suitable for G omega-seal recording. Whole-cell current-clamp and voltage-clamp recordings indicated that the cells remained electrically excitable after dissociation. Cell-attached recordings frequently revealed single-channel openings in the presence of dopamine or of the D2 dopamine agonist ...

This study determined the role of ventral tegmental area acetylcholine and glutamate receptors in modulating laterodorsal tegmentum stimulation-evoked dopamine efflux in the nucleus accumbens. Rapid changes in dopamine oxidation current were measured at carbon fiber microelectrodes using fixed potential amperometry in urethane anesthetized male mice. Intraventral tegmental area infusions of the...

1. The pharmacology of the acute hyperthermia that follows 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') administration to rats has been investigated. 2. MDMA (12.5 mg kg(-1) i.p.) produced acute hyperthermia (measured rectally). The tail skin temperature did not increase, suggesting that MDMA may impair heat dissipation. 3. Pretreatment with the 5-HT(1/2) antagonist methysergide (10 mg k...

Injection of NMDAR antagonist into the thalamus can produce delta frequency EEG oscillations in the thalamocortical system. It is surprising that an antagonist of an excitatory neurotransmitter should trigger such activity, and the mechanism is unknown. One hypothesis is that the antagonist blocks excitation of GABAergic cells, thus producing disinhibition. To test this hypothesis, we investiga...

The aim of the present study was to clarify whether pharmacological preconditioning with dopamine protects the heart against ischemia and whether this effect is mediated through dopaminergic receptors (D1 and D2) or alpha1-adrenoceptors. Isolated perfused rat hearts were either non-preconditioned, preconditioned with 5 min ischemia, or treated for 5 min with dopamine (1, 5 or 10 microM) before ...

Dopamine has been demonstrated to be involved in the modulation of long-term potentiation (LTP) in the CA1 region of the hippocampus. As monoamine transporter blockade will increase the actions of endogenous monoamine neurotransmitters, the effect of a dopamine transporter (DAT) antagonist on LTP was assessed using field excitatory postsynaptic potentials recorded in the CA1 region of the rat h...

Neurotransmitter transporters play an important role in maintaining synaptic homeostasis and in the actions of many drugs. Utilizing a technique for measuring the kinetics (synthesis, degradation, and half-life) of the dopamine transporter (DAT) protein in the rat striatum and nucleus accumbens, we have investigated the effects of systemic administration of dopamine receptor agonists and antago...