RESUMEN
INTRODUCTION: Prostatic carcinoma (PC) is a frequent neoplasm in elderly patients. Although androgen deprivation is associated with survival benefits, it is also related to adverse effects such as osteoporosis, frailty, or sarcopenia, which can negatively affect the patient's quality of life. This study aims to quantify and evaluate the prevalence of osteoporosis, frailty, or sarcopenia in elderly PC patients before and after androgen deprivation. We present data from an interim analysis. MATERIALS AND METHODS: PROSARC is a national (Spain) prospective observational study (May-2022-May-2025) still in progress in 2 hospitals. It includes patients with high-risk PC, aged ≥70 years, non-candidates for local treatment and scheduled to start androgen deprivation therapy. The following variables are analyzed: comorbidity, frailty (Fried frailty phenotype criteria), osteoporosis, sarcopenia (EWGSOP2), fat mass and muscle mass, before treatment and after 6 months of follow-up. RESULTS: A 6-month follow-up was completed by 12/25 included patients (mean age, 84 years), with a high baseline prevalence of pre-frailty/frailty (67.7%), sarcopenia (66.7%) and osteoporosis (25%). Treatment did not significantly alter these variables or comorbidity. We observed changes in body mass index (p=0.666), decreased mean value of appendicular muscle mass (p=0.01) and increased percentage of fat mass (p=0.012). CONCLUSION: In patients with high-risk PC, advanced age and a considerable prevalence of osteoporosis, frailty and sarcopenia, androgen deprivation (ADT; 6 months) produces decreased muscle mass without impact on the incidence of the known adverse effects of androgen deprivation.
Asunto(s)
Antagonistas de Andrógenos , Osteoporosis , Neoplasias de la Próstata , Sarcopenia , Masculino , Humanos , Antagonistas de Andrógenos/efectos adversos , Antagonistas de Andrógenos/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Estudios Prospectivos , Anciano de 80 o más Años , Anciano , Sarcopenia/epidemiología , Sarcopenia/inducido químicamente , Osteoporosis/inducido químicamente , Osteoporosis/epidemiología , Prevalencia , Medición de Riesgo , Fragilidad/epidemiología , Fragilidad/inducido químicamenteRESUMEN
Sodium butyrate is a sodium salt of a volatile short-chain fatty acid (butyric acid) used to prevent Salmonella Enteritidis infection in birds. Three groups of fifty 1-d-old broilers each were fed the following diets: T0 = standard broiler diet (control); T1 = standard broiler diet supplemented with 0.92 g/kg of an additive with free sodium butyrate (Gustor XXI B92); and T2 = standard broiler diet supplemented with 0.92 g/kg of an additive with sodium butyrate partially protected with vegetable fats (Gustor XXI BP70). Twenty percent of the birds were orally infected with Salmonella Enteritidis at d 5 posthatching and fecal Salmonella shedding was assessed at d 6, 9, 13, 20, 27, 34, and 41 of the trial. At d 42, all birds were slaughtered and 20 of them dissected: crop, cecum, liver, and spleen were sampled for bacteriological analyses. Both butyrate-based additives showed a significant reduction (P < 0.05) of Salmonella Enteritidis infection in birds from d 27 onward. However, the partially protected butyrate additive was more effective at the late phase of infection. Partially protected butyrate treatment successfully decreased infection not only in the crop and cecum but also in the liver. There were no differences in the spleen. These results suggest that sodium butyrate partially protected with vegetable fats offers a unique balance of free and protected active substances effective all along the gastrointestinal tract because it is slowly released during digestion.
Asunto(s)
Butiratos/farmacología , Pollos , Suplementos Dietéticos , Enfermedades de las Aves de Corral/prevención & control , Salmonelosis Animal/prevención & control , Salmonella enteritidis , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Heces/microbiología , Femenino , Masculino , Salmonelosis Animal/microbiologíaRESUMEN
1. Effects of the aporphinoid alkaloid, (+)-glaucine, on rat vas deferens were investigated. 2. (+)-Glaucine (2-18 microM) competitively inhibited contractions induced by noradrenaline and methoxamine with a pA2 value of about 6. 3. (+)-Glaucine (2 and 18 microM) did not change the accumulation of tritium during incubation of the vas deferens with [3H]-noradrenaline. 4. (+)-Glaucine (0.3 nM-0.1 mM) inhibited specific [3H]-prazosin binding to membranes from rat vas deferens with a pKi value of 6.63, which is close to the pA2 value obtained against noradrenaline and methoxamine in functional studies. 5. In electrically-stimulated rat vas deferens, (+)-glaucine (0.3-10 microM) enhanced twitch contractions and competitively antagonized the inhibitory effect of clonidine with a pA2 value of 5.91. 6. In tissues incubated in depolarizing calcium-free high-potassium medium, (+)-glaucine (30-80 microM) inhibited Ca(2+)-induced contractions with depression of the maximal response at higher doses and with a pD'2 value of 3.65. Furthermore, (+)-glaucine (50 microM) did not modify basal 45Ca uptake but strongly inhibited the influx of 45Ca induced by K+. 7. These results suggest that (+)-glaucine has non-selective alpha 1- and alpha 2-adrenoceptor blocking properties. At higher doses, (+)-glaucine shows calcium antagonist activity which may be responsible, at least in part, for the inhibition of the contractions induced by Ca2+ in calcium-free high-potassium medium.
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Antitusígenos/farmacología , Aporfinas/farmacología , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Parasimpatolíticos/farmacología , Conducto Deferente/efectos de los fármacos , Animales , Calcio/metabolismo , Calcio/farmacocinética , Cloruro de Calcio/farmacología , Radioisótopos de Calcio , Membrana Celular/metabolismo , Estimulación Eléctrica , Hidroxilaminas/farmacología , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Relajación Muscular/fisiología , Músculo Liso/fisiología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Norepinefrina/farmacocinética , Norepinefrina/farmacología , Prazosina/metabolismo , Ratas , Ratas Sprague-Dawley , Tritio , Conducto Deferente/metabolismo , Conducto Deferente/fisiologíaRESUMEN
The activation of GABAB receptors hyperpolarizes 5-HT neurons and reduces cell firing. In situ hybridization showed the presence of the GABAB-RI receptor transcript in virtually all 5-HT neurons of the dorsal and median raphe nuclei (DR and MnR, respectively) whereas the GAD transcript was present mainly outside these nuclei. The systemic administration of baclofen increased the in vivo 5-HT release in the DR, MnR and several projection areas. As shown previously in the DR, the application of baclofen in the MnR increased the local 5-HT output. Thus, although 5-HT neurons contain inhibitory GABAB-RI receptors, baclofen increased 5-HT release in some brain areas, likely by a preferential action on terminal GABAB autoreceptors in inhibitory inputs to 5-HT neurons. The scarcity of GAD-expressing cells in the DR and MnR suggests that these inputs originate mainly outside these nuclei.
Asunto(s)
Baclofeno/farmacología , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Agonistas del GABA/farmacología , Proteínas de Transporte de Membrana , Proteínas del Tejido Nervioso , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Receptores de GABA-B/efectos de los fármacos , Receptores de GABA-B/genética , Serotonina/metabolismo , Animales , Encéfalo/citología , Proteínas Portadoras/genética , Relación Dosis-Respuesta a Droga , Glutamato Descarboxilasa/genética , Masculino , Glicoproteínas de Membrana/genética , Microdiálisis , ARN Mensajero/metabolismo , Núcleos del Rafe/citología , Núcleos del Rafe/efectos de los fármacos , Núcleos del Rafe/metabolismo , Ratas , Ratas Wistar , Proteínas de Transporte de Serotonina en la Membrana Plasmática , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
A series of cyproheptadine related compounds was synthesized and tested pharmacologically. In comparison with cyproheptadine, these compounds do not have a central ring and some contain groups other than N-methyl. Synthesis was carried out with low-valent titanium to generate the exocyclic double bond. The serotoninergic activity of the compounds was determined by standard determination of pA2 (-log of the motor concentration of antagonist required to maintain a constant response when concentration of agonist is doubled) for the inhibition of serotonin-induced contractions in rat stomach fundus. Two of the nitrogen-containing compounds were active, but their activities were lower than that of cyproheptadine. Structure-activity relationships were studied by Mulliken net charges, molecular electrostatic potentials, and conformational analysis; activities are better correlated with electrostatic potentials than with net charges. The decrease in potency of the open cyproheptadine analogues may be due to "dilution" of the active conformer as the result of their conformational flexibility.
Asunto(s)
Ciproheptadina/análogos & derivados , Antagonistas de la Serotonina/síntesis química , Animales , Ciproheptadina/síntesis química , Ciproheptadina/farmacología , Masculino , Conformación Molecular , Ratas , Ratas Sprague-Dawley , Antagonistas de la Serotonina/farmacología , Relación Estructura-ActividadRESUMEN
In the present paper, a fully latent polyphenol oxidase (PPO) from desert truffle (Terfezia claveryi Chatin) ascocarps is described for the first time. The enzyme was partially purified by using phase partitioning in Triton X-114 (TX-114). The achieved purification was 2-fold from a crude extract, with a 66% recovery of activity. The interfering lipids were reduced to 13% of the original content. In addition, the purification gave rise to a reduction of phenolic compounds to only 37.5%, thus avoiding the postpurification tanning of the enzyme. Latent PPO was activated by the anionic surfactant sodium dodecyl sulfate (SDS) or by incubation with trypsin. The amount of SDS necessary to obtain a maximum activation was dependent on the nature of the substrate. The use of SDS also permitted the histochemical localization of the latent enzyme within the ascocarp. Terfezia polyphenol oxidase was kinetically characterized using two phenolic substrates (L-DOPA and tert-butylcatechol). The latter substrate presented inhibition at high substrate concentration with a K(si) of 6.3 mM. Different inhibiting agents (kojic and cinnamic acid, mimosine and tropolone) were also studied, tropolone being the most effective.
Asunto(s)
Ascomicetos/enzimología , Catecol Oxidasa/aislamiento & purificación , Detergentes/química , Polietilenglicoles/química , Catecol Oxidasa/análisis , Catecol Oxidasa/metabolismo , Activación Enzimática , Histocitoquímica , Cinética , Octoxinol , Dodecil Sulfato de Sodio/químicaRESUMEN
Macro and microscopic features for 21 species of ectomycorrhizal fungi are presented, with regard to their particular importance as possible taxonomic criteria. The culture media used are MMN and BAF. Cultural characteristics of some of our isolates, like color or morphology of the mycelia, were comparable to those observed by different authors for the same species, or species which are closely related taxonomically, as for example Boletus satanas and Lactarius deliciosus in BAF media, or Hebeloma edurum, Lycoperdon perlatum, Paxillus atrotomentosus, Rhizopogon roseolus and Suillus collinitus in MMN media. Macroscopically the color of mycelia, the amount of aerial mycelia and microscopically the exudates and the presence of inflated and flexuous cells were the most variable characteristics within species.
RESUMEN
We describe the clinical case of a patient with acute myocardial infarction treated with t-PA fibrinolysis, who developed renal failure and cutaneous lesions of the livedo reticularis type, probably caused by embolization of cholesterol crystals. The main characteristics of this rare clinical entity are reviewed.
Asunto(s)
Embolia por Colesterol/complicaciones , Infarto del Miocardio/tratamiento farmacológico , Insuficiencia Renal/etiología , Enfermedades Cutáneas Vasculares/etiología , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/complicaciones , Terapia TrombolíticaRESUMEN
Central nervous system depression is the predominant response to acute trichloroethylene exposure. Cranial or peripheral nerves are also affected. The paper is a case report of a bilateral retrobulbar optic neuritis caused by occupational trichloroethylene poisoning. The urinary concentration of trichloroacetic acid one week after the onset of symptoms was positive. Visual fields and visual evoked potentials recovered eight months later. Other neurological diseases, such as multiple sclerosis were excluded.
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Enfermedades Profesionales/inducido químicamente , Neuritis Óptica/inducido químicamente , Solventes/efectos adversos , Tricloroetileno/efectos adversos , Enfermedad Aguda , Adulto , Humanos , Masculino , Enfermedades Profesionales/diagnóstico , Neuritis Óptica/diagnóstico , Factores de TiempoRESUMEN
This paper describes for the first time the ectomycorrhiza synthesized between two Guatemalan strains of Lactarius indigo (Schw.) Fr. and the Neotropical species Pinus ayacahuite var. ayacahuite Ehren, P. hartwegii Lindl., P. oocarpa Schiede ex Schltdl. var oocarpa, P. pseudostrobus Lindl. and P. rudis Endl. The synthesis was carried out in a controlled growth chamber using plastic containers with peat moss-vermiculite substrate and mycelial inoculum. Mycorrhiza were obtained 25 days after inoculation. A description of the morphology, appearance and structure of mantle and Hartig net is given for each combination. Mycorrhiza were saffron to cinnamon greenish with age, with a net of saffron laticifers visible through outer mantle; orange latex secreted when injured. Cystidia-like emanating hyphae were observed on the mantle surface of young mycorrhiza. Plectenchymatous mantle with abundant interhyphal gelatinous material.
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Agaricales/crecimiento & desarrollo , Micorrizas/crecimiento & desarrollo , Pinus/microbiología , Agaricales/citología , Hifa/crecimiento & desarrollo , Microscopía Electrónica de Rastreo , Micorrizas/fisiología , Micorrizas/ultraestructura , Fotograbar , Pigmentación , Pinus/anatomía & histología , Pinus/ultraestructura , Raíces de Plantas/anatomía & histología , Raíces de Plantas/microbiología , Raíces de Plantas/ultraestructuraRESUMEN
This work presents the first anatomical description of the mycorrhizal systems of Helianthemum almeriense, and of the structure and ultrastructure of the mycorrhizae formed by this plant species with the ascomycetes Terfezia claveryi and Picoa lefebvrei. Four different mycorrhizal systems are described, the club-shaped mycorrhiza being the most abundant. The type of mycorrhiza formed depended on the mycorrhiza culture conditions, but not on the fungal species. For both fungal species, H. almeriense formed an endomycorrhiza in natural field conditions, an ecto- and ectendomycorrhiza without a sheath in pot cultures, and an ectomycorrhiza with a characteristic sheath and Hartig net in in vitro cultures. This is the first report of a typical sheath in Helianthemum-desert truffle mycorrhizal associations. The results support the idea that culture conditions can induce changes in mycorrhiza morphology and that there is no clear barrier between the two main types of mycorrhiza organization in Helianthemum species. The ultrastructural study confirmed the regular presence of T. claveryi intracellular hyphae in direct contact with the host wall, a localization which seems to be a characteristic of the T. claveryi mycorrhiza organization. The P. lefebvrei mycorrhiza organization was characterized by intracellular hyphae with large amounts of electron-dense globules, probably with a lipidic content, and a warty ornamentation on the wall of the root external hyphae.
Asunto(s)
Ascomicetos/ultraestructura , Cistaceae/microbiología , Micorrizas/ultraestructura , Cistaceae/ultraestructura , Hifa/ultraestructura , Microscopía Electrónica , Raíces de Plantas/microbiología , Raíces de Plantas/ultraestructuraRESUMEN
Twenty isolates of Verticillium fungicola var. fungicola collected from diseased fruit-bodies of Agaricus bisporus from prochloraz-treated crops, were exposed to a range of concentrations of six chemicals (benomyl, chlorothalonil, formaldehyde, iprodione, prochloraz-Mn-complex and prochloraz + carbendazim) in vitro. EC(50) values were determined for each fungus-fungicide combination. All isolates were more sensitive to prochloraz-Mn-complex (EC(50) values less than 5 mg 1(-1)) than to the remainder fungicides, and only seven isolates were moderately sensitive (EC(50) values between 5 and 50 mg 1(-1)) to prochloraz + carbendazim. All isolates were moderately sensitive to formaldehyde, whereas the majority of isolates were very resistant to the other three fungicides (benomyl, chlorothalonil and iprodione).
RESUMEN
The ftsZ gene was cloned from the chromosomal DNA of Brevibacterium lactofermentum by the polymerase chain reaction (PCR) using two oligonucleotides designed from two conserved regions found in most of the previously cloned and sequenced ftsZ genes from other microorganisms. ftsZ is a single-copy gene in corynebacteria and is located downstream from ftsQ and murC, indicating linkage between genes involved in peptidoglycan synthesis (mur genes) and genes involved in cell division (fts genes). The organisation of the cluster is similar to that in Streptomyces and different from those of Escherichia coli or Bacillus subtilis because ftsA is not located upstream of ftsZ. The gene was expressed in E. coli using the T7 expression system; the calculated molecular weight of the expressed protein was 50 kDa. Expression of the B. lactofermentum ftsZ gene in E. coli inhibited cell division and led to filamentation. The ftsZ gene of this organism does not complement ftsZ mutations or deletions in E. coli, when cloned on low or high-copy-number vectors.
Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Brevibacterium/genética , Cromosomas Bacterianos/química , Proteínas del Citoesqueleto , Secuencia de Aminoácidos , Secuencia de Bases , Western Blotting , División Celular/genética , Clonación Molecular , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Genes Bacterianos , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/biosíntesis , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Transcripción GenéticaRESUMEN
Embryos of Rana perezi were kept under laboratory conditions and treated with carbamate ZZ-Aphox at chronic doses of 0.02% and 0.14% for 9 weeks. Both the histological study and the analysis of mortality show a direct relationship between the dosage and the effects of the pesticide. The histological study of the survivors over 56 days show damages in gills, liver, gall-bladder, heart, and notochord. Damages on the epithelial of gills (on their distal portion) and gall-bladder recover over a few days, whereas those provoked on the compacting of the hepatic parenchyma and the hepatocytes, the auricle and the perintocohordal collagenic fibers alter their structure in a lasting way. Potentials of such alterations are discussed, with special reference to the possible interference of the pesticide on the successful synthesis of the supporting connective sheaths.
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Carbamatos/toxicidad , Vesícula Biliar/patología , Larva/efectos de los fármacos , Hígado/patología , Notocorda/patología , Pirimidinas , Ranidae , Animales , Vesícula Biliar/efectos de los fármacos , Hígado/efectos de los fármacos , Notocorda/efectos de los fármacos , Tasa de SupervivenciaRESUMEN
Tadpoles of Rana perezi were kept for 14 weeks in water containing two sublethal levels of the carbamate insecticide ZZ-Aphox or the organophosphate Folidol. Approximate concentrations of their active ingredients were 0.25 and 1 mg/L. Resulting malformations were studied by skeletal analysis and histological and histochemical investigation of te rear limbs of the tadpoles. The pesticides caused the animals to have malformations of the spinal column (scoliosis) and/or limbs (short and thick long bones with the epiphyses grossly twisted). Histochemical study showed differences in the composition of the connective matrix, and microscopic examination of the long bones indicated alterations in the thickness of the uncalcified bone matrix (osteoid) and the presence of abundant vascularised connective tissue in the region of the periosteum. The results confirmed changes in the composition of the connective tissue matrix as the cause of the defects observed in bone formation which are also discussed in relation to vitamin D absorption and calcium homeostasis.
Asunto(s)
Anomalías Inducidas por Medicamentos , Huesos/efectos de los fármacos , Carbamatos/toxicidad , Insecticidas/toxicidad , Metil Paratión/toxicidad , Pirimidinas , Animales , Huesos/anomalías , Femenino , Larva , Deformidades Congénitas de las Extremidades , Masculino , Ranidae , Columna Vertebral/anomalías , Columna Vertebral/efectos de los fármacosRESUMEN
The three ORFs (YFIH, ORF5 and ORF6) located downstream of the cell division genes ftsQ and ftsZ in Brevibacterium lactofermentum were disrupted by single homologous recombination events between internal fragments of the corresponding genes and the chromosomal sequences. The phenotypes of the disrupted mutants were similar to that of the wild type, suggesting that these genes are dispensable for growth and viability. However, using different plasmid constructs, it was not possible to obtain disrupted ftsZ or ftsQ mutants by single crossover events. When the ftsZ or ftsQ gene sequence was disrupted in vitro and used to replace the homologous chromosomal gene by double recombination, only single recombination events took place, and therefore no disruptants were obtained. It may be concluded therefore that, as in Escherichia coli, the cell division genes ftsQ and ftsZ are indispensable for growth and viability of B. lactofermentum. Northern hybridisation analyses performed using internal fragments of the genes coding for YFIH, ORF5 and ORF6 allowed us to dissect their transcriptional organization and to confirm the disruption of these genes.
Asunto(s)
Adhesión Bacteriana , Proteínas Bacterianas/genética , Brevibacterium/crecimiento & desarrollo , Brevibacterium/genética , Proteínas del Citoesqueleto , Proteínas de Escherichia coli , Proteínas de la Membrana/genética , Sistemas de Lectura Abierta , Secuencia de Bases , Brevibacterium/citología , División Celular/genética , Cromosomas Bacterianos/genética , Clonación Molecular , Cartilla de ADN , Escherichia coli/genética , Eliminación de Gen , Genes Bacterianos , Genes Esenciales , Genotipo , Plásmidos , Recombinación Genética , Transcripción GenéticaRESUMEN
The distribution of histamine H(2) receptor mRNA was determined by in situ hybridization histochemistry in human and monkey brain. In the case of monkey brain, we combined this technique with receptor ligand autoradiography to compare the distribution of mRNA and receptor binding sites. [(125)I]Iodoaminopotentidine ([(125)I]-APT), a reversible, high specific activity antagonist with high affinity and selectivity for the H(2) receptor, was used for receptor autoradiography. Radiolabeled oligonucleotides derived from the human mRNA sequence encoding this receptor were used as hybridization probes. The highest density of the H(2) receptor mRNA in human and monkey brain was found in caudate and putamen nuclei and external layers of cerebral cortex. Moderate levels were seen in the hippocampal formation and lower densities in the dentate nucleus of cerebellum. Areas such as globus pallidus, amygdaloid complex, cerebellar cortex, and substantia nigra were devoid of hybridization signal. The distribution of H(2) receptor mRNA in monkey brain is generally in good agreement with that of the corresponding binding sites: prominent in caudate, putamen, accumbens nuclei, and cortical areas. The hippocampus showed lower densities of receptors and low levels were detected in the globus pallidus pars lateralis. No binding sites were seen in amygdaloid complex and substantia nigra. The distribution of histaminergic innervation is in good correlation with the areas of high density for H(2) receptors: caudate, putamen, and external layers of cerebral cortex in monkey and human brain. The presence of mRNA in caudate and putamen nuclei, together with its absence from substantia nigra, suggests that the H(2) receptors found in the striatum are synthesized by intrinsic cells and not by nigral dopaminergic cells. These striatal H(2) receptors may be located on short circuit striatal interneurons or somatodendritically on striatal projection neurons which project to the globus pallidus pars lateralis. In conclusion, the present results, which constitute, to our knowledge, the first report of the regional distribution of mRNA encoding H(2) receptors detected by in situ hybridization, define the sites of synthesis of H(2) receptors and are the basis for future, more detailed studies that should result in a better understanding of H(2) receptor function.
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Química Encefálica , Neuronas/química , ARN Mensajero/análisis , Receptores Histamínicos H2/análisis , Adulto , Anciano , Anciano de 80 o más Años , Animales , Femenino , Humanos , Hibridación in Situ , Macaca fascicularis , Masculino , Persona de Mediana EdadRESUMEN
We studied the control of dorsal raphe (DR) serotonergic neurons by dopaminergic transmission in rat brain using microdialysis and single unit extracellular recordings. Apomorphine (0.5-3.0 mg/kg s.c.) and quinpirole (0.5 mg/kg s.c.) increased serotonin (5-HT) output in the DR and (only apomorphine) in striatum. These effects were antagonized by 0.3 mg/kg s.c. SCH 23390 (in DR and striatum) and 1 mg/kg s.c. raclopride (in DR). 5-HT(1A) receptor blockade potentiated the 5-HT increase produced by apomorphine in the DR. Apomorphine (50-400 microg/kg i.v.) increased the firing rate of most 5-HT neurons, an effect prevented by SCH 23390 and raclopride. Quinpirole (40-160 microg/kg i.v.) also enhanced the firing rate of 5-HT neurons. When applied in the DR, neither drug increased the 5-HT output in the DR or striatum. Likewise, micropressure injection of quinpirole (0.2-8 pmol) failed to increase the firing rate of 5-HT neurons. In situ hybridization showed that the dopamine (DA) D(2) receptor transcript was almost absent in the DR and abundant in the substantia nigra (SN) and the periaqueductal grey matter (PAG). Using dual probe microdialysis, the application of tetrodotoxin or apomorphine in SN significantly increased the DR 5-HT output. Thus, the discrepancy between local and systemic effects of dopaminergic agonists and the absence of DA D(2) receptor transcript in 5-HT neurons suggest that DA D(2) receptors outside the DR control serotonergic activity.