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We present evidence that intermittent administration of nicotine, 2 mg/kg s.c., four times daily to mice for 14 days produces a somatic abstinence syndrome after discontinuing treatment. The nicotine abstinence was mild and protracted, lasting more than 92 h. The constellation of abstinence signs was characterized by rearing, jumping, shakes, abdominal(More)
In mice administered chronic stress--repeated overnight restraint stress for 7 days--there was a prolonged enhancement of dopamine (DA) uptake into synaptosomes. The mRNA for the DA transporter (DAT) was found to be concomitantly increased in the midbrain, as was the binding of the transporter ligand mazindol to DAT in the nucleus accumbens and(More)
Incubation with either of the protein kinase C activators phorbol 12-myristate 13-acetate (PMA) and sn-1,2 dioctanoylglycerol (DiC8) decreased the uptake of dopamine into striatal synaptosomes, whereas the inactive phorbol ester 4 alpha-PMA had no effect. Washout of PMA and DiC8 failed to reverse the decrease in uptake. Kinetic analysis showed a decrease in(More)
Following the administration of a single dose of diisopropylfluorophosphate (DFP) there is a rise of acetylcholine (ACh) in the rat striatum and frontal cortex. With chronic treatment, striatal ACh content returns to normal, but frontal cortex ACh remains elevated. In striatum but not frontal cortex, there is a rise of dopamine (DA) content and turnover(More)
RATIONALE Nicotine displays rewarding and aversive effects, and while dopamine has been linked with nicotine's reward, the neurotransmitter(s) involved with aversion remains speculative. The kappa-dynorphinergic system has been associated with negative motivational and affective states, and whether dynorphin (Dyn) contributes to the behavioral pharmacology(More)
Aromatic L-amino acid decarboxylase (AAAD) activity of rat retina increases when animals are placed in a lighted environment from the dark. The increase of activity can be inhibited by administering the selective dopamine D1 receptor agonist SKF 38393, but not the selective D2 agonist quinpirole, or apomorphine. Conversely, in the dark, enzyme activity can(More)
The acidic metabolites of dopamine, homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC), are present in rat retina. DOPAC is the most abundant metabolite. Both metabolites increase in parallel when rats are taken from a dark to a lighted environment. Haloperidol treatment also increases the metabolites in both dark and light while apomorphine(More)
Nicotine withdrawal causes somatic and negative affective symptoms that contribute to relapse and continued tobacco smoking. So far, the neuronal substrates involved are not fully understood, and an opioid role has been suggested. In this regard, the opioid dynorphin (Dyn) is of interest as it produces aversive states and has been speculated to play a role(More)
Aromatic L-amino acid decarboxylase (AAAD) is an essential enzyme for the formation of catecholamines, indolamines, and trace amines. Moreover, it is a required enzyme for converting L-DOPA to dopamine when treating patients with Parkinson's disease (PD). There is now substantial evidence that the activity of AAAD in striatum is regulated by activation and(More)
Clozapine is efficacious for treating dopaminergic psychosis in Parkinson's disease and ameliorates l-DOPA-induced motor complications. Based on its pharmacology and reported enhancing effects on dopamine metabolism and tyrosine hydroxylase activity, we investigated whether it could modulate the activity of aromatic l-amino acid decarboxylase (AAAD), the(More)