BIOMAT Database Logo BIOMAT Database Logo

Effects of 5-HT and 8-OH-DPAT on forebrain monoamine synthesis after local application into the median and dorsal raphe nuclei of the rat. 1990

V Hillegaart, and S Hjorth, and S Ahlenius
Department of Psychology, University of Göteborg, Sweden.

5-HT (10 and 40 micrograms) and 8-OH-DPAT (1 and 5 micrograms) were locally applied into the dorsal or median raphe nuclei in awake, unrestrained, rats. All animals were also treated with the 5-HTP and DOPA decarboxylase inhibitor NSD-1015, 100 mg kg-1 SC, 30 min before decapitation. 5-HT or 8-OH-DPAT were administered 5 min before NSD-1015. The regional brain in vivo rate of tyrosine and tryptophan hydroxylase activity was estimated by measuring the accumulation of DOPA and 5-HTP. The following brain regions were sampled: neocortex, hippocampus, dorso-lateral neostriatum, ventro-medial neostriatum, nucleus accumbens, olfactory tubercle, globus pallidus, septum and the amygdala. Compared to normal controls, there were small and inconsistent effects on forebrain 5-HTP accumulation by saline injections into the dorsal or the median raphe (an increase in 3 out of 36 experiments), whereas strong effects by the injection procedure were noted on forebrain DOPA accumulation (an increase in 15 out of 36 experiments). Injections of 5-HT (same effect by 10 or 40 micrograms) into the dorsal raphe, produced a decrease in 5-HTP accumulation in all forebrain areas except for the hippocampus and the septum, whereas no effects were seen in any area after median raphe injections. In contrast, 8-OH-DPAT preferentially produced a decrease in forebrain 5-HTP accumulation after median raphe injections and less, but statistically significant effects by dorsal raphe injections. The 8-OH-DPAT injection into the median raphe primarily affected limbic forebrain areas (hippocampus, nucleus accumbens, ventro-medial neostriatum, amygdala and the septum). This dissociation of the effects of 5-HT and 8-OH-DPAT on forebrain 5-HT synthesis after local application into the dorsal or the median raphe strongly supports the contention of heterogeniety in the brain 5-HT receptor population in terms of receptor subtypes and/or receptor regulation.

UI MeSH Term Description Entries
D008297 Male Males
D009281 Naphthalenes Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.
D011903 Raphe Nuclei Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA. Caudal Linear Nucleus of the Raphe,Interfascicular Nucleus,Nucleus Incertus,Rostral Linear Nucleus of Raphe,Rostral Linear Nucleus of the Raphe,Superior Central Nucleus,Central Nucleus, Superior,Incertus, Nucleus,Nuclei, Raphe,Nucleus, Interfascicular,Nucleus, Raphe,Nucleus, Superior Central,Raphe Nucleus
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D002395 Catecholamines A general class of ortho-dihydroxyphenylalkylamines derived from TYROSINE. Catecholamine,Sympathin,Sympathins
D004295 Dihydroxyphenylalanine A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific. Dopa,3,4-Dihydroxyphenylalanine,3-Hydroxy-DL-tyrosine,Dihydroxyphenylalanine Hydrochloride, (2:1),beta-Hydroxytyrosine,3 Hydroxy DL tyrosine,3,4 Dihydroxyphenylalanine,beta Hydroxytyrosine
D004791 Enzyme Inhibitors Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D005625 Frontal Lobe The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus. Brodmann Area 8,Brodmann's Area 8,Frontal Cortex,Frontal Eye Fields,Lobus Frontalis,Supplementary Eye Field,Area 8, Brodmann,Area 8, Brodmann's,Brodmanns Area 8,Cortex, Frontal,Eye Field, Frontal,Eye Field, Supplementary,Eye Fields, Frontal,Frontal Cortices,Frontal Eye Field,Frontal Lobes,Lobe, Frontal,Supplementary Eye Fields
D006834 Hydrazines Substituted derivatives of hydrazine (formula H2N-NH2). Hydrazide
D006916 5-Hydroxytryptophan The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant. 5-HTP,Hydroxytryptophan,Oxitriptan,Oxytryptophan,Tryptophan, 5-Hydroxy-,5 Hydroxytryptophan,5-Hydroxy- Tryptophan,Tryptophan, 5 Hydroxy

Related Publications

V Hillegaart, and S Hjorth, and S Ahlenius
Effects of local application of 5-HT and 8-OH-DPAT into the dorsal and median raphe nuclei on core temperature in the rat.
January 1991, Psychopharmacology,
V Hillegaart, and S Hjorth, and S Ahlenius
Effects of local application of 5-HT and 8-OH-DPAT into the dorsal and median raphe nuclei on motor activity in the rat.
July 1990, Physiology & behavior,
V Hillegaart, and S Hjorth, and S Ahlenius
Effects of local application of 5-HT into the median and dorsal raphe nuclei on male rat sexual and motor behavior.
July 1989, Behavioural brain research,
V Hillegaart, and S Hjorth, and S Ahlenius
Effects of 8-OH-DPAT, 5-CT and muscimol on behaviour maintained by a DRL20 schedule of reinforcement, following microinjection into the dorsal or median raphe nuclei.
June 1994, Behavioural pharmacology,
V Hillegaart, and S Hjorth, and S Ahlenius
Stimulation of median, but not dorsal, raphe 5-HT1A autoreceptors by the local application of 8-OH-DPAT reverses raclopride-induced catalepsy in the rat.
May 1995, Neuropharmacology,
V Hillegaart, and S Hjorth, and S Ahlenius
Effects of local application of 5-hydroxytryptamine into the dorsal or median raphe nuclei on haloperidol-induced catalepsy in the rat.
January 1999, Neuropharmacology,
V Hillegaart, and S Hjorth, and S Ahlenius
Effect of local injection of 8-OH-DPAT into the dorsal or median raphe nuclei on extracellular levels of serotonin in serotonergic projection areas in the rat brain.
March 1992, Neuroscience letters,
V Hillegaart, and S Hjorth, and S Ahlenius
Chronic administration of the 5-HT1A receptor agonist 8-OH-DPAT differentially desensitizes 5-HT1A autoreceptors of the dorsal and median raphe nuclei.
February 1997, Synapse (New York, N.Y.),
V Hillegaart, and S Hjorth, and S Ahlenius
Voltammetric study of 8-OH-DPAT effect on the raphe-trigeminal 5-HT system.
June 1992, Neuroreport,
V Hillegaart, and S Hjorth, and S Ahlenius
A single dose of 8-OH-DPAT reduces raphe binding of [3H]8-OH-DPAT and increases the effect of raphe stimulation on 5-HT metabolism.
March 1990, European journal of pharmacology,
Copied contents to your clipboard!