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Female Wistar rats were allowed to self-administer nicotine solutions through indwelling jugular vein cannulae for 23 h per day for periods from three to five weeks. Two response levers were available to the rats; responding on one lever, designated the active lever, produced an immediate infusion of nicotine solution or saline. A second lever for which(More)
The effects of opioid agonists with selectivity for kappa, mu and delta types of opioid receptors on the K+-stimulated release of [3H]dopamine (DA) from striatum and cortex of rat and guinea pig loaded previously with the monoamine have been studied. The kappa agonist U50488H did not affect base-line release of [3H]DA measured in 5 mM K+, but produced a(More)
Release of preloaded radiolabeled dopamine ([3H]DA) elicited by several agents from terminal fields of mesolimbic and nigrostriatal projections in rats was compared. Several similarities between the two areas were observed. For example, potassium, which stimulates release both directly, through altering the potential across the membrane of the dopaminergic(More)
1. Morphine produces a plethora of pharmacological effects and its chronic administration induces several side-effects. The cellular mechanisms by which opiates induce these side-effects are not fully understood. Several studies suggest that regulation of adenylyl cyclase activity by opioids and other transmitters plays an important role in the control of(More)
Antibodies directed against the C-terminal and the N-terminal regions of the mu-opioid receptor were generated to identify the G proteins that coimmunoprecipitate with the mu receptor. Two fusion proteins were constructed: One contained the 50 C-terminal amino acids of the mu receptor, and the other contained 61 amino acids near the N terminus of the(More)
It is thought that inhibition of dopamine reuptake into neurons may play a major role in the mechanisms by which cocaine produces its reinforcing effects. The striatum, while rich in dopamine terminals, is not implicated in drug reinforcement, whereas the mesolimbic dopamine pathway appears to play a primary role. It is therefore possible that the(More)
Potassium (K (+)) channels can regulate ionic conduction through their pore by a mechanism, involving the selectivity filter, known as C-type inactivation. This process is rapid in the hERG K (+) channel and is fundamental to its physiological role. Although mutations within hERG are known to remove this process, a structural basis for the inactivation(More)
It has been postulated that endogenous opioids play a pathophysiological role in spinal cord injury, based on the therapeutic effects of the opiate receptor antagonist naloxone in certain experimental models. The high doses of naloxone required to exert a therapeutic action suggest that naloxone's effects may be mediated by non-mu opiate receptors, such as(More)
The effect of a series of indoleamines on the potassium-evoked tritium release of previously accumulated [3H]dopamine from rat striatal slices has been investigated. The indoleamines 5-hydroxytryptamine, 5-methoxytryptamine, 5-methoxy-N,N'-dimethyltryptamine and tryptamine (10(-7) to 10(-5) M) all reduced potassium-evoked release of tritium, to a maximum of(More)
1. Intrahypothalamic injection of either dopamine or noradrenaline in a dose volume of 1 mul. caused a fall in core temperature in lightly restrained rats maintained at an ambient temperature of 17 +/- 1 degrees C.2. The hypothermic effects of dopamine (10 mug) and noradrenaline (2 mug) were selectively antagonized by systemic pre-treatment with pimozide(More)