Circadian rhythm of [3H]imipramine binding in the rat suprachiasmatic nuclei

Wirz‐Justice, Anna; Kräuchi, Kurt; Morimasa, Tadaomi; Willener, Rosi; Feer, H.

doi:10.1016/0014-2999(83)90348-5

Cited by 59 publications

(15 citation statements)

References 6 publications

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“…Increased activity in 5-HT uptake has been reported in male rats during the onset of the active phase of the circadian cycle (Meyer & Quay, 1976). Similarly there is a peak in imipramine binding to the 5-HT uptake system at this time (Wirz-Justice, Krauchi, Morimasa, Willener & Feer, 1983). These biochemical changes are reflected in electrophysiological observations found for s.c.n.…”

Section: Discussionmentioning

confidence: 85%

Circadian variation in sensitivity of suprachiasmatic and lateral geniculate neurones to 5‐hydroxytryptamine in the rat.

Mason¹

1986

The Journal of Physiology

104

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SUMMARY1. Extracellular single-unit recordings were obtained from neurones in the suprachiasmatic nuclei (s.c.n.) of the rat (a putative circadian pace-maker), the ventral lateral geniculate nucleus (v.l.g.n.) and the hippocampus. These areas receive a 5-hydroxytryptamine (5-HT) innervation from the raphe nuclei. Recording of neuronal activity in the s.c.n., v.l.g.n. and the hippocampus revealed a diurnal variation in the response to the ionophoresis of 5-HT. This variation was manifest as a 2-3-fold increase in post-synaptic sensitivity to 5-HT during the subjective dark (active) phase of the circadian cycle. In contrast there was no apparent circadian variation in the sensitivity of s.c.n., v.l.g.n. or hippocampal neurones to ionophoresed y-aminobutyric acid (GABA).2. Neuronal activity recorded in the s.c.n., v.l.g.n. and hippocampus also exhibited a circadian variation in the recovery from 5-HT-induced suppression of firing. This may reflect reuptake processes as recovery can be prolonged by ionophoresis of uptake blockers (imipramine or fluoxetine).3. Rats (n = 15) expressing circadian arrhythmicity in theirrest-activity behaviour induced by long-term continuous illumination (150-200 lx) showed no apparent circadian variation in 5-HT sensitivity. This loss was accompanied by either the development of (i) a 5-6-fold subsensitivity to ionophoresed 5-HT (eleven out of fifteen rats) or (ii) a 2-3-fold supersensitivity to ionophoresed 5-HT (four out of fifteen rats).4. A similar loss of circadian variation and the development of a subsensitivity to ionophoresed 5-HT was also found in three rats sustaining complete electrolytic lesions of the s.c.n. These changes were not found in rats (n = 4) with partial s.c.n. lesions.5. These results implicate the s.c.n., or fibres passing through it, in the circadian modulation of 5-HT sensitivity in neurones both intrinsic to the s.c.n. circadian pace-maker itself and in the hippocampus and lateral geniculate nucleus (regions remote from the s.c.n.).

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Section: Discussionmentioning

confidence: 85%

Circadian variation in sensitivity of suprachiasmatic and lateral geniculate neurones to 5‐hydroxytryptamine in the rat.

Mason¹

1986

The Journal of Physiology

104

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“…In particular, the midbrain raphe complex shows higher expression levels than other areas (Bengel et al, 1997). Concerning the circadian change of SERT expression, 3 H-labeled imipramine binding sites showed marked increase in suprachiasmatic nuclei of the anterior hypothalamus during the dark phase (Wirz-Justice et al, 1983).…”

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confidence: 94%

Chronopharmacological Study of Antidepressants in Forced Swimming Test of Mice

Ushijima

Sakaguchi

Sato

et al. 2005

J Pharmacol Exp Ther

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The influence of dosing time on the anti-immobility effect of antidepressants and mechanisms underlying this phenomenon were investigated in mice. In the forced swimming test (FST), the immobility time of mice treated with amitriptyline (15 mg/kg) and fluvoxamine (30 mg/kg) showed a significant 24-h rhythm. The anti-immobility effect of fluvoxamine in FST was potent at the early part of the dark phase without increasing locomotor activity. Concerning pharmacokinetics, although K e of fluvoxamine was approximately 1.3-fold higher in mice injected with fluvoxamine at 9:00 PM than at 9:00 AM, no dosing time dependence was demonstrated for either plasma or brain fluvoxamine concentration at 0.5 h after the drug injection. On the other hand, serotonin transporter (SERT) mRNA expression and 5-hydroxytryptamine (5-HT) uptake activity in the mouse midbrain showed significant time-dependent changes with higher levels during the dark phase and lower levels during the light phase. These results suggest that the reuptake of 5-HT might be more increased during the dark phase. Since the reuptake of 5-HT is inhibited almost completely by injection with 30 mg/kg fluvoxamine at any time, the extracellular 5-HT level may be more increased by the injection of fluvoxamine at the early part of the dark phase. The present results suggest that the antiimmobility effect of fluvoxamine in FST increases depending on dosing time. Furthermore, the time-dependent change of SERT mRNA expression and uptake activity in the midbrain is suggested to be the mechanism underlying the 24-h rhythm of anti-immobility effect of fluvoxamine.

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“…Intragastric administration of imipramine, a serotonin reuptake blocker, was found to lengthen and enhance the inhibitory action of serotonin in the SCN (Meijer & Groos, 1988). Studies by Wirz-Justice, Krauchi, Morimesa, Willener & Feer (1983) demonstrated that serotonin receptors in the SCN have a temporal sensitivity to imipramine binding which peaks during the night phase in the rat.…”

mentioning

confidence: 99%

Serotonin regulates the phase of the rat suprachiasmatic circadian pacemaker in vitro only during the subjective day.

Medanic

Gillette

1992

The Journal of Physiology

151

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SUMMARY1. The suprachiasmatic nucleus (SCN) of the hypothalamus is the primary pacemaker for circadian rhythms in mammals. The 24 h pacemaker is endogenous to the SCN and persists for multiple cycles in the suprachiasmatic brain slice.2. While serotonin is not endogenous to the SCN, a major midbrain hypothalamic afferent pathway is serotonergic. Within this tract the dorsal raphe nucleus sends direct projections to the ventrolateral portions of the SCN. We investigated a possible regulatory role for serotonin in the mammalian circadian system by examining its effect, when applied at projection sites, on the circadian rhythm of neuronal activity in rat SCN in vitro.3. Eight-week-old male rats from our inbred colony, housed on a 12 h light: 12 h dark schedule, were used. Hypothalamic brain slices containing the paired SCN were prepared in the day and maintained in glucose and bicarbonate-supplemented balanced salt solution for up to 53 h. 4. A 1011 ml drop of 10-6 M-serotonin (5-hydroxytryptamine (5-HT) creatinine sulphate complex) in medium was applied to the ventrolateral portion of one of the SCN for 5 min on the first day in vitro. The effect of the treatment at each of seven time points across the circadian cycle was examined. The rhythm of spontaneous neuronal activity was recorded extracellularly on the second and third days in vitro. Phase shifts were determined by comparing the time-of-peak of neuronal activity in serotonin-vs. media-treated slices.5. Application of serotonin during the subjective day induced significant advances in the phase of the electrical activity rhythm (n = 11). The most sensitive time of treatment was CT 7 (circadian time 7 is 7 h after 'lights on' in the animal colony), when a 70 + 0-1 h phase advance was observed (n = 3). This phase advance was perpetuated on day 3 in vitro without decrement. Serotonin treatment during the subjective night had no effect on the timing of the electrical activity rhythm (n= 9).6. The specificity of the serotonin-induced phase change was assessed by treating t To whom correspondence should be addressed. MS 9615M. MEDANIC AND M. U. GILLETTE slices in the same manner with a microdrop of serotonergic agonists, 5-carboxamidotryptamine, that targets the 5-HT1 class of receptors, or 8-hydroxydipropylaminotetralin (8-OH DPAT), that acts on the 5-HTlA receptor subtype. Daytime (CT 9) application of 5-carboxamidotryptamine resulted in a 6-0+001 h phase advance (n = 3), while treatment during the subjective night (CT 15, n = 2) had little observable effect. Similarly, treatment with 8-OH DPAT at CT 9 induced a phase advance of 69 + 01 h (n = 3) in the rhythm of electrical activity.7. These results demonstrate that serotonin can induce large phase changes in the SCN circadian pacemaker and that the SCN undergoes endogenous changes in sensitivity to serotonin. The data suggest that serotonergic inputs to the ventrolateral SCN can regulate the circadian pacemaker during the daytime.

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Circadian rhythm of [3H]imipramine binding in the rat suprachiasmatic nuclei

Cited by 59 publications

References 6 publications

Circadian variation in sensitivity of suprachiasmatic and lateral geniculate neurones to 5‐hydroxytryptamine in the rat.

Circadian variation in sensitivity of suprachiasmatic and lateral geniculate neurones to 5‐hydroxytryptamine in the rat.

Chronopharmacological Study of Antidepressants in Forced Swimming Test of Mice

Serotonin regulates the phase of the rat suprachiasmatic circadian pacemaker in vitro only during the subjective day.

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