Homeostatic regulation of serotonergic function by the serotonin transporter as revealed by nonviral gene transfer.
With the aim of exploring the relationship between the serotonin transporter (5-HTT or SERT) and the activity level of serotonin (5-HT) neurotransmission, in vivo expression of this protein was specifically altered using a nonviral DNA transfer method. Plasmids containing the entire coding sequence or a partial antisense sequence of the 5-HTT gene were complexed with the cationic polymer polyethylenimine and injected into the dorsal raphe nucleus of adult male rats. Significant increase or decrease in both [(3)H]citalopram binding and [(3)H]5-HT synaptosomal uptake were observed in various brain areas up to 2 weeks after a single administration of the sense plasmid or 7 d after injection of the short antisense plasmid, respectively. Such changes in 5-HTT expression were associated with functional alterations in 5-HT neurotransmission, as shown by the increased capacity of 5-HT(1A) receptor stimulation to enhance [(35)S]GTP-gamma-S binding onto the dorsal raphe nucleus in sections from rats injected with the sense plasmid. Conversely, both a decrease in 5-HT(1A)-mediated [(35)S]GTP-gamma-S binding and a reduced potency of the 5-HT(1A) receptor agonist ipsapirone to inhibit neuronal firing were observed in the dorsal raphe nucleus of antisense plasmid-injected rats. Furthermore, changes in brain 5-HT and/or 5-HIAA levels, and sleep wakefulness circadian rhythm in the latter animals demonstrated that altered expression of 5-HTT by recombinant plasmids has important functional consequences on central 5-HT neurotransmission in adult rats.
Fabre
V
V
Institut National de la Santé et de la Recherche Médicale U288, Neuropsychopharmacologie Moléculaire, Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, 75634 Paris Cedex 13, France. v.fabre@scripps.edu
Boutrel
B
B
Hanoun
N
N
Lanfumey
L
L
Fattaccini
C M
CM
Demeneix
B
B
Adrien
J
J
Hamon
M
M
Martres
M P
MP
D000818:Animals; D001345:Autoradiography; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002540:Cerebral Cortex / Q000502:physiology*; D015283:Citalopram / Q000493:pharmacokinetics; D016373:DNA, Antisense; D004298:Dopamine / Q000378:metabolism; D018014:Gene Transfer Techniques; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006706:Homeostasis; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010957:Plasmids; D011743:Pyrimidines / Q000494:pharmacology; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000502:physiology; D044263:Receptors, Serotonin, 5-HT1; D011994:Recombinant Proteins / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013552:Swine; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014162:Transfection
D002352:Carrier Proteins; D016373:DNA, Antisense; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011743:Pyrimidines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D011994:Recombinant Proteins; D050486:Serotonin Plasma Membrane Transport Proteins; D017366:Serotonin Receptor Agonists; C493232:Slc6a4 protein, rat; D015283:Citalopram; D012701:Serotonin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C043077:ipsapirone; D004298:Dopamine