D1‐and D2‐dopamine receptors exert important physiological actions on striatal neurons, but the intracellular second messenger pathways activated by these receptors are still incompletely understood. Using primary cultures of rat striatal cells, we have examined the effects of activating D1 or D2 receptors on arachidonic acid (AA) release and cyclic AMP accumulation. In striatal neurons labeled by incubation with [3H]AA, D2‐receptor stimulation enhanced release of [3H]AA produced by application of the Ca2+ ionophore A23187 or of the purinergic agonist ATP. By contrast, D1‐receptor stimulation inhibited [3H]AA release. This inhibitory effect of D1 receptors was accompanied by stimulation of adenylyl cyclase activity, measured as accumulation of cyclic AMP, and was mimicked by application of the adenylyl cyclase activator forskolin. The results indicate the existence of a novel signaling pathway for D2 and D1 receptors in striatum, potentiation and inhibition, respectively, of Ca2+‐evoked AA release.

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Fifty-nine depressed female inpatients were treated with 100 mg amitriptyline (AMT) IM for 4 weeks. Depression ratings and determinations of the parent drug and nortriptyline (NT) were performed weekly. No direct relationship between plasma AMT + NT concentrations and therapeutic response was apparent, but beneficial therapeutic responses and significantly lower side-effect scores were more frequently noted in subjects with concentrations in the 100-200 ng/ml range. AMT + NT concentrations were significantly correlated with age. No significant difference was found in the number of responders between younger and older subjects with two clinical improvement criteria; however, a significant difference emerged when a third more restrictive clinical outcome criterion was adopted. The implications of the present findings for patient treatment and for the interpretation of previous studies are discussed. The data collected point to a possible usefulness of monitoring AMT and NT plasma levels, even if further investigations are needed.

We studied the effect of alprazolam (APZ) in 12 healthy volunteers on the psychological stress-induced activation of emotion and on the pituitary-adrenal, adrenomedullary and sympathoneuronal systems. After 3 days of placebo or APZ (1 mg/day orally) administration, we examined plasma levels of adre-nocorticotropic hormone, cortisol, L-3,4 dihydroxyphenylalanine, dopamine, norepinephrine (NE), epinephrine, metanephrine, normetanephrine, homovanillic acid, vanillylmandelic acid, 3-methoxy-4-hydroxy phenylglycol, urinary levels of cortisol and catecholamines, circulatory responses and state anxiety levels in subjects undergoing psychological stress based on viewing horror, violence, danger and war film clips. Film viewing produced modest rises of state anxiety levels, of plasma NE concentration and of diastolic blood pressure in both the placebo and drug groups. APZ significantly reduced anxiety levels at the beginning of the experimental session and caused a decrease of noradrenergic and dopaminergic neurotransmitter and cortisol concentrations. Our data suggest that APZ reduced anxiety related to the expectation of the event, while the circuitry between structures responsible for anxiety and peripheral sympathoneural function was still found to be partly sensitive to film viewing.