Usage patterns of phototherapy in seasonal affective disorder.

We mailed a questionnaire to patients affected with seasonal affective disorder (SAD) to determine patterns of self-selected light use and efficacy of treatment. Data obtained from 127 patients who responded indicate that despite, inconvenience and other use-limiting factors, many patients with SAD derive sustained benefit from phototherapy over months. No consistent pattern or duration of effective treatment emerged. Development of a less cumbersome means of delivering phototherapy and reimbursement by insurance companies remain concerns to patients.

Determination of the source of 5-hydroxytryptaminergic neuronal projections to the neural and intermediate lobes of the rat pituitary gland through the use of electrical stimulation and lesioning experiments.

5-Hydroxytryptamine (5-HT)-containing axons and terminals have been visualized in the neural and intermediate lobes of the rat pituitary gland, but the origin of these fibers remains in question. This study was designed to determine if 5-HT cell bodies in the brainstem or in the dorsomedial nucleus of the hypothalamus project to either of these pituitary lobes. Since lesions and electrical stimulation of 5-HT cell bodies decrease and increase, respectively, the rate of 5-HT synthesis in regions innervated by these cells, these techniques were employed. The in vivo rate of 5-HT synthesis was determined by quantifying the rate of accumulation of the 5-HT precursor, 5-hydroxytryptophan (5-HTP), in the neural and intermediate lobes of the pituitary gland 30 min after the administration of a decarboxylase inhibitor (NSD 1015, 100 mg/kg, i.p.). The application of 30 min of stimulating current (monophasic cathodal pulses of 1 ms duration and 0.3 mA current delivered at a frequency of 10 Hz) to electrodes implanted in the dorsal and median raphe nuclei increased the rate of 5-HT synthesis in both the neural and intermediate lobes of the pituitary gland. 5,7-Dihydroxytryptamine lesions of these nuclei altered neither 5-HTP accumulation nor 5-HT concentrations in the neural and intermediate lobes, but similar lesions of the nuclei raphe pontis and raphe magnus decreased both the concentration of 5-HT and the accumulation of 5-HTP in these pituitary regions.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Hydroxytryptamine is synthesized in neurons terminating in the neural and intermediate lobes of the rat pituitary gland.

Immunocytochemistry has revealed that nerve fibers within the neural and intermediate lobes of the rat pituitary gland contain 5-hydroxytryptamine (5-HT). Recent anatomical evidence suggests that the content of this amine in the intermediate but not the neural lobe of the pituitary gland may represent 5-HT that has been taken up from the blood rather than synthesized intraneuronally. The purpose of this study was to determine if 5-HT is synthesized in neurons of the neurointermediate lobe of the pituitary gland. 5-HT synthesis was estimated by measuring the accumulation of the 5-HT precursor, 5-hydroxytryptophan (5-HTP), in the neurointermediate lobe of male Long-Evans rats following the administration of NSD 1015, an inhibitor of aromatic L-amino acid decarboxylase. Thirty min following the injection of NSD 1015 (100 mg/kg, i.p.), 5-HTP accumulated in the neurointermediate lobe and the rate of this accumulation was increased by the administration of the 5-HTP precursor, tryptophan, and by electrical stimulation of the pituitary stalk. In addition, repeated injections of the 5-HT uptake inhibitor, fluoxetine (10 mg/kg, i.p., every 12 h for a total of 7 injections), induced a marked depletion of platelet 5-HT but did not alter the concentration of 5-HT in either the neural or intermediate lobes of the pituitary gland. Taken together these results indicate that much of the 5-HT in the neurointermediate lobe of the pituitary gland does not represent 5-HT taken up from the blood, but rather the amine is synthesized in neurons projecting to this region.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of biochemical indices of 5-hydroxytryptaminergic neuronal activity following electrical stimulation of the dorsal raphe nucleus.

The activity of 5-hydroxytryptaminergic neurons has been estimated from measurements of: concentrations of 5-hydroxyindoleacetic acid; the ratio of the concentrations of 5-hydroxyindoleacetic acid to 5-hydroxytryptamine; the rate of accumulation of 5-hydroxytryptophan following the administration of an aromatic L-amino acid decarboxylase inhibitor (e.g., NSD 1015); the rate of accumulation of 5-hydroxytryptamine, and the rate of decline of 5-hydroxyindoleacetic acid following the administration of a monoamine oxidase inhibitor (e.g., pargyline). The purpose of the present study was to compare these different methods under conditions of changing neuronal impulse traffic produced by electrical stimulation of 5-hydroxytryptaminergic neurons. Male rats anesthetized with chloral hydrate were killed following 0, 15, or 30 min of electrical stimulation of the dorsal raphe nucleus at a frequency of 0, 5, or 10 Hz. The concentrations of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophan in nucleus accumbens, amygdala, suprachiasmatic nucleus, and dorsomedial nucleus were measured using HPLC coupled to an electrochemical detector. In each brain region, stimulation elicited an increase in the concentration of 5-hydroxyindoleacetic acid and the 5-hydroxyindoleacetic acid/5-hydroxytryptamine concentration ratio in saline-treated animals and an increase in 5-hydroxytryptophan accumulation in NSD 1015-treated animals, but did not alter the concentration of 5-hydroxytryptamine or 5-hydroxyindoleacetic acid in pargyline-treated rats. The results o f this study indicate that although the first three methods serve as valid indices of 5-hydroxytryptaminergic neuronal activity, the pargyline-dependent techniques are not responsive to changes in the rate of 5-hydroxytryptamine nerve firing.

Exogenous tryptophan increases synthesis, storage, and intraneuronal metabolism of 5-hydroxytryptamine in the rat hypothalamus.

The effects of tryptophan administration on neurochemical estimates of synthesis [5-hydroxytryptophan (5-HTP) accumulation following administration of a decarboxylase inhibitor], storage [5-hydroxytryptamine (5-HT) concentrations], and metabolism [5-hydroxyindoleacetic acid (5-HIAA) concentrations] of 5-HT in selected regions of the hypothalamus were determined using HPLC coupled to an electrochemical detector. Tryptophan methyl ester HCl (30-300 mg/kg i.p.) produced a dose-dependent increase in the rate of 5-HTP accumulation throughout the hypothalamus but had no effect on the rate of accumulation of 3,4-dihydroxyphenylalanine. Peak 5-HTP levels were attained by 30 min following administration of tryptophan (100 mg/kg i.p.) and were maintained for an additional 60 min. Tryptophan also produced concomitant dose-dependent increases in 5-HT and 5-HIAA concentrations in these same regions without changes in the 5-HIAA/5-HT ratio. These results indicate that exogenous tryptophan administration selectively increases the synthesis, storage, and metabolism of 5-HT in the hypothalamus without altering the synthesis of catecholamines. Inhibition of 5-HT uptake with chlorimipramine or fluoxetine produced modest (10-40%) reductions in 5-HIAA concentrations throughout the hypothalamus, revealing that only a minor portion of 5-HIAA is derived from released and recaptured 5-HT, whereas the major portion of this metabolite reflects intraneuronal metabolism of unreleased 5-HT. In both chlorimipramine- and fluoxetine-treated rats, 5-HIAA concentrations were significantly increased by tryptophan administration, indicating that the increase in synthesis of 5-HT following precursor loading is accompanied by an increase in the intraneuronal metabolism of 5-HT.

Effects of acute and chronic bupropion on locomotor activity and dopaminergic neurons.

Acute administration of bupropion (10 or 30 mg/kg) to rats increased locomotor activity in a dose-related manner. The highest dose increased the dopamine (DA) concentration while both doses reduced the concentration of dihydroxyphenylacetic acid (DOPAC) in the striatum. The enhancement of locomotor activity and the decrease of striatal DOPAC concentrations were increased with chronic administration (up to 40 days) of bupropion. The rate of DA synthesis in the striatum was increased by the acute administration of d-amphetamine but was not altered by acute or chronic administration of bupropion.