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We have investigated the pharmacology underlying locomotor system responses to serotonin (5-HT) in embryos of the frog, Rana temporaria, to provide a comparison to studies in embryos of its close relative, Xenopus laevis. Our findings suggest that two divergent mechanisms underlie the modulation of locomotion by 5-HT in Rana. Bath-applied 5-HT or 5-carboxamidotyptamine, a 5-HT(1,5A,7) receptor agonist, can modulate fictive swimming in a dose-dependent manner, increasing burst durations and cycle periods. However, activation of 5-HT(1,7) receptors with R8-OHDPAT or 8-OHDPAT fails to mimic 5-HT, and in some cases exerts exactly the opposite response; decreasing burst durations and cycle periods. Elevating endogenous 5-HT levels by blocking re-uptake with clomipramine transiently increases burst durations. The receptors involved in this endogenous response include 5-HT(1A) receptors, as in Xenopus, but also 5-HT(7) receptors. However, like the 8-OHDPAT enantiomers, prolonged re-uptake inhibition can result in a motor response in the opposite direction to exogenous 5-HT. This effect is not reversed by 5-HT(1A) and/or 5-HT(7) receptor antagonism, implicating 5-HT(1B/1D) receptors. Remarkably, antagonism of these receptors using methiothepin unmasks a dose-dependent response to clomipramine, reminiscent of exogenous 5-HT. Our data suggest that 5-HT(1A,7) and 5-HT(1B/1D) receptors act as gain-setters of burst durations, whilst 5-HT(5A) receptors are involved in the effects of bath-applied 5-HT on locomotion.
Adell,
Origin and functional role of the extracellular serotonin in the midbrain raphe nuclei.
2002, Pubmed
Adell,
Origin and functional role of the extracellular serotonin in the midbrain raphe nuclei.
2002,
Pubmed
Bacon,
5-Hydroxytryptamine(7) receptor activation decreases slow afterhyperpolarization amplitude in CA3 hippocampal pyramidal cells.
2000,
Pubmed
Barbeau,
Tapping into spinal circuits to restore motor function.
1999,
Pubmed
Barnes,
A review of central 5-HT receptors and their function.
1999,
Pubmed
Boothby,
The stopping response of Xenopus laevis embryos: pharmacology and intracellular physiology of rhythmic spinal neurones and hindbrain neurones.
1992,
Pubmed
,
Xenbase
Bunin,
Quantitative evaluation of 5-hydroxytryptamine (serotonin) neuronal release and uptake: an investigation of extrasynaptic transmission.
1998,
Pubmed
Bunin,
Paracrine neurotransmission in the CNS: involvement of 5-HT.
1999,
Pubmed
Christenson,
Increase in endogenous 5-hydroxytryptamine levels modulates the central network underlying locomotion in the lamprey spinal cord.
1989,
Pubmed
Dale,
Experimentally derived model for the locomotor pattern generator in the Xenopus embryo.
1995,
Pubmed
,
Xenbase
Duncan,
Localization of serotonin(5A) receptors in discrete regions of the circadian timing system in the Syrian hamster.
2000,
Pubmed
Eglen,
The 5-HT7 receptor: orphan found.
1997,
Pubmed
el Manira,
Calcium-dependent potassium channels play a critical role for burst termination in the locomotor network in lamprey.
1994,
Pubmed
Fischer,
Adrenoreceptor-mediated modulation of the spinal locomotor pattern during swimming in Xenopus laevis tadpoles.
2001,
Pubmed
,
Xenbase
Grailhe,
Increased exploratory activity and altered response to LSD in mice lacking the 5-HT(5A) receptor.
1999,
Pubmed
Hammar,
Modulation of responses of feline ventral spinocerebellar tract neurons by monoamines.
2002,
Pubmed
Honda,
Differential effects of (R)- and (S)-8-hydroxy-2-(di-n-propylamino)tetralin on the monosynaptic spinal reflex in rats.
1999,
Pubmed
Jacobs,
Serotonin and motor activity.
1997,
Pubmed
Kahn,
The central nervous origin of the swimming motor pattern in embryos of Xenopus laevis.
1982,
Pubmed
,
Xenbase
Kahn,
The neuromuscular basis of rhythmic struggling movements in embryos of Xenopus laevis.
1982,
Pubmed
,
Xenbase
Katz,
The evolution of neuronal circuits underlying species-specific behavior.
1999,
Pubmed
Kuenzi,
The pharmacology and roles of two K+ channels in motor pattern generation in the Xenopus embryo.
1998,
Pubmed
,
Xenbase
Lovenberg,
A novel adenylyl cyclase-activating serotonin receptor (5-HT7) implicated in the regulation of mammalian circadian rhythms.
1993,
Pubmed
McDearmid,
Aminergic modulation of glycine release in a spinal network controlling swimming in Xenopus laevis.
1997,
Pubmed
,
Xenbase
McLean,
Spinal and supraspinal functions of noradrenaline in the frog embryo: consequences for motor behaviour.
2003,
Pubmed
Merrywest,
Mechanisms underlying the noradrenergic modulation of longitudinal coordination during swimming in Xenopus laevis tadpoles.
2003,
Pubmed
,
Xenbase
Merrywest,
Alpha-adrenoreceptor activation modulates swimming via glycinergic and GABAergic inhibitory pathways in Xenopus laevis tadpoles.
2002,
Pubmed
,
Xenbase
Pauwels,
Stereoselectivity of 8-OH-DPAT enantiomers at cloned human 5-HT1D receptor sites.
1996,
Pubmed
Perrier,
5-HT1A receptors increase excitability of spinal motoneurons by inhibiting a TASK-1-like K+ current in the adult turtle.
2003,
Pubmed
Price,
Species differences in 5-HT autoreceptors.
1996,
Pubmed
Rees,
Cloning and characterisation of the human 5-HT5A serotonin receptor.
1994,
Pubmed
Roberts,
How does a nervous system produce behaviour? A case study in neurobiology.
1990,
Pubmed
,
Xenbase
Roberts,
Ligands for the investigation of 5-HT autoreceptor function.
2001,
Pubmed
Rossignol,
Pharmacological aids to locomotor training after spinal injury in the cat.
2001,
Pubmed
Schmidt,
The role of serotonin in reflex modulation and locomotor rhythm production in the mammalian spinal cord.
2000,
Pubmed
Sillar,
Control of frequency during swimming in Xenopus embryos: a study on interneuronal recruitment in a spinal rhythm generator.
1993,
Pubmed
,
Xenbase
Sillar,
Presynaptic inhibition of primary afferent transmitter release by 5-hydroxytryptamine at a mechanosensory synapse in the vertebrate spinal cord.
1994,
Pubmed
,
Xenbase
Sillar,
Electrical coupling and intrinsic neuronal oscillations in Rana temporaria spinal cord.
1994,
Pubmed
Soffe,
Centrally generated rhythmic and non-rhythmic behavioural responses in Rana temporaria embryos.
1991,
Pubmed
Soffe,
Patterns of synaptic drive to ventrally located spinal neurones in Rana temporaria embryos during rhythmic and non-rhythmic motor responses.
1991,
Pubmed
Soffe,
Ionic and pharmacological properties of reciprocal inhibition in Xenopus embryo motoneurones.
1987,
Pubmed
,
Xenbase
Sun,
Developmental changes in expression of ion currents accompany maturation of locomotor pattern in frog tadpoles.
1998,
Pubmed
,
Xenbase
Sun,
Differential inhibition of N and P/Q Ca2+ currents by 5-HT1A and 5-HT1D receptors in spinal neurons of Xenopus larvae.
1998,
Pubmed
,
Xenbase
Talley,
Postnatal development of serotonergic innervation, 5-HT1A receptor expression, and 5-HT responses in rat motoneurons.
1997,
Pubmed
Teshiba,
Dual and opposing modulatory effects of serotonin on crayfish lateral giant escape command neurons.
2001,
Pubmed
Tsou,
Cloning and expression of a 5-hydroxytryptamine7 receptor positively coupled to adenylyl cyclase.
1994,
Pubmed
van Mier,
The development of serotonergic raphespinal projections in Xenopus laevis.
1986,
Pubmed
,
Xenbase
Veasey,
Single-unit responses of serotonergic dorsal raphe neurons to specific motor challenges in freely moving cats.
1997,
Pubmed
Vizuete,
Expression of 5-HT7 receptor mRNA in rat brain during postnatal development.
1997,
Pubmed
Wall,
A slowly activating Ca(2+)-dependent K+ current that plays a role in termination of swimming in Xenopus embryos.
1995,
Pubmed
,
Xenbase
Wikström,
The action of 5-HT on calcium-dependent potassium channels and on the spinal locomotor network in lamprey is mediated by 5-HT1A-like receptors.
1995,
Pubmed
