Localization of 5-HT1B, 5-HT1D alpha, 5-HT1E and 5-HT1F receptor messenger RNA in rodent and primate brain.
In situ hybridization histochemistry (ISHH) was used to study the distribution of various 5-HT1 receptor messenger RNAs (mRNA) in the mammalian nervous system. Since the cDNAs encoding the different 5-HT1 receptors, have not been cloned in one single species, brains of the species appropriate for the 5-HT1 receptor messenger RNA (mRNA) have been used. Thus, 5-HT1B and 5-HT1D alpha mRNA were determined in rat and mouse brain, while 5-HT1E and 5-HT1F mRNA were studied in human (and monkey) and guinea-pig brain, respectively. 5-HT1B and 5-HT1D alpha hybridization signals were predominantly present in caudate-putamen and cortical areas; in addition, 5-HT1B mRNA was also detected in hippocampus, cerebellum and cerebral arteries. In general, the distribution of 5-HT1B mRNA was characterized by high densities, whereas 5-HT1D alpha mRNA was expressed at very low levels. Comparison of the localization of the mRNAs to the regional distributions of the 5-HT1B and 5-HT1D binding sites in rat brain (described in a previous study), revealed that both receptor subtypes could be putative presynaptic heteroreceptors, modulating the release of various neurotransmitters in the central nervous system. The mRNA encoding the recently cloned 5-HT1E receptor, which has low affinity for the 5-HT1 receptor ligand 5-carboxamidotryptamine (5-CT), was localized in human brain. It was found to be present in cortical areas, caudate, putamen and amygdala, areas known to contain 5-CT insensitive 5-HT1 binding sites. The regional distribution of the 5-HT1F mRNA was determined in guinea-pig brain: high densities were observed in various cortical areas, the hippocampal formation and claustrum, which are regions known to contain 5-CT insensitive 5-HT1 or non 5-HT1A/1B/IC/ID [3H]5-HT binding sites. Altogether, this ISHH study describes the distribution of mRNAs of recently cloned 5-HT1 receptors in rodent and primate brain and compares these results to the distribution of the heterogeneous population of 5-HT1 binding sites.
Bruinvels
A T
AT
Preclinical Research 360/604, Sandoz Pharma Ltd, Basel, Switzerland.
Landwehrmeyer
B
B
Gustafson
E L
EL
Durkin
M M
MM
Mengod
G
G
Branchek
T A
TA
Hoyer
D
D
Palacios
J M
JM
D000818:Animals; D001921:Brain / Q000033:anatomy & histology*; D001923:Brain Chemistry / Q000502:physiology*; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D006168:Guinea Pigs; D000882:Haplorhini; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000096:biosynthesis*
D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D011985:Receptors, Serotonin