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Biomedical subjects

M Carli

Publications and source records attributed to M Carli.

At least 91 records · Page 5Linked to original sources
PubMed1993

Localized but unresectable neuroblastoma: treatment and outcome of 145 cases. Italian Cooperative Group for Neuroblastoma.

PURPOSE: To define factors that influence outcome in children with localized but unresectable neuroblastoma by retrospective investigation of response to therapy and outcome in 21 Italian institutions. PATIENTS AND METHODS: Of 145 assessable children diagnosed between 1979 and 1990, 77 were treated between 1979 and 1984 with three consecutive standard-dose (SD) protocols, and 68 between 1985 and 1990 with a high-dose (HD) protocol. All protocols included chemotherapy, followed by resection of primary tumor if feasible. If at least partial resection was achieved, consolidation therapy followed, except that from 1985 onward, patients considered disease-free following surgery received no further treatment. RESULTS: Ninety-four of 145 patients (65%) achieved a complete response (CR) or partial response (PR) with chemotherapy and 75 (52%) subsequently underwent complete resection of the primary tumor. Eighty-one patients are alive (73 without disease, eight with disease), 63 have died, and one is lost to follow-up. The 5-year overall survival (OS) rate is 55% and progression-free survival (PFS) rate 50%. Both OS and PFS correlated with response to chemotherapy, removal of primary tumor, HD therapy, and serum lactate dehydrogenase (LDH) levels. Infants (< 1 year), independent of primary tumor site, and children aged 1 to 15 years with a nonabdominal primary tumor, did better compared with children aged 1 to 15 years with an abdominal primary tumor (PFS, 72% and 64% v 30%; P < .001 and < .01, respectively). Outcome of this last group improved with the HD protocol (PFS, 40% v 23%; P = .01). CONCLUSION: In children with unresectable neuroblastoma, risk categories can be defined by age and primary tumor site. HD chemotherapy should be investigated for the poor-risk category age 1 to 15 years with an abdominal primary tumor.

Adolescent↗
PubMed1992

Stimulation of 5-HT1A receptors in the dorsal hippocampus impairs acquisition and performance of a spatial task in a water maze.

8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a potent 5-HT1A receptor agonist, was infused in the dorsal hippocampus of rats and its effect on acquisition and performance of a 2-platform spatial discrimination task was studied using a water maze. The infusion (0.5 microliter/min) of 2 but not 0.4 microgram 8-OH-DPAT in the CA1 region of the dorsal hippocampus impaired rats' accuracy with no effect on latency (except day 3). At 5 micrograms 8-OH-DPAT impaired rats' accuracy and significantly increased choice latencies from day 2 to day 5 of the training period. The dose of 2 micrograms significantly increased the errors of omissions on the first day of training and animals which had received 5 micrograms 8-OH-DPAT made significantly more errors of omission on the first and second days of training. Intrahippocampal administration of 1 microgram spiroxatrine, a 5-HT1A receptor antagonist, antagonized the effect of 5 micrograms 8-OH-DPAT on accuracy and choice latency with no significant effect on the errors of omission on days 1 and 2 of training. Infusion of 2 and 5 micrograms 8-OH-DPAT in the dorsal hippocampus also impaired accuracy in well-trained rats. The results suggest that stimulation of 5-HT1A receptors in the CA1 region of the dorsal hippocampus causes an impairment of spatial discrimination in rats.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Disseminated neuroblastoma (stage IV and IV-S) in the first year of life. Outcome related to age and stage. Italian Cooperative Group on Neuroblastoma.

BACKGROUND: Infants (age 0-11 months) with disseminated neuroblastoma are known to have a better prognosis than older children with the disease, but there is little information regarding factors that influence the outcome of the disease in these patients. METHODS: The authors report a series of 110 infants with disseminated neuroblastoma with disease diagnosed between March 1976 and February 1991 in 21 institutions participating in the Italian Cooperative Group on Neuroblastoma (ICGNB). Of the 110 infants, 34 had Stage IV disease, and 76 had Stage IV-S disease. RESULTS: The 5-year survival probability was 77% for all patients, 71% for those with Stage IV disease, and 81% for those with Stage IV-S disease. Of the 34 infants with Stage IV disease, the 9 who were 5 months or younger at the time of disease diagnosis are all alive (1 with active disease) at 7-143 months after diagnosis, whereas of the 25 infants who were 6-11 months of age at the time of disease diagnosis, 10 have died. Of the 76 infants with Stage IV-S disease, 12/64 who were 5 months of age or younger at the time of disease diagnosis died (mostly of massive hepatomegaly); 9 of these deaths occurred in infants with disease diagnosed before they were 2 months old, whereas 1 death occurred in the 12 infants with disease diagnosed when they were 6-11 months old. Four infants with Stage IV-S disease achieved complete disease remission and subsequently had relapse of disease. High levels of serum LDH and low urinary excretion of vanillylmandelic acid were associated with worse prognosis. CONCLUSIONS: The authors suggest that infants older than 6 months of age who have Stage IV disease require aggressive therapy. For infants with disease diagnosed before they are 2 months old, Stage IV-S disease may have a worse prognosis than Stage IV disease.

Age Factors↗
PubMed1992

Preoperative care of infants with nephroblastoma. The International Society of Pediatric Oncology 6 experience.

The International Society of Pediatric Oncology (SIOP) recommends preoperative treatment in the management of eligible patients with Wilms' tumor. Until 1980, children younger than 12 months of age (infants) at diagnosis had been excluded from the SIOP trials. SIOP 6, conducted from 1980 to 1987, was the first SIOP study to include infants older than 6 months of age. This retrospective analysis of 145 infants registered to SIOP 6 demonstrates that in infants older than 6 months and having favorable histology (FH), a two-drug preoperative chemotherapy (CT) regimen of 4 weeks significantly ameliorated stage distribution as determined at delayed surgery but did not affect a good outcome. However, the CT dose utilized in SIOP 6 resulted in an unacceptable toxicity in this age group, and SIOP 9, the new SIOP study of Wilms' tumor, recommends a reduced dose of CT in infants. Preoperative CT is not recommended in infants younger than 6 months of age. Specifically, the high incidence (29%) of mesoblastic nephroma in this age group does not justify such an approach. Histopathologic diagnosis should be obtained in these patients before any treatment.

Age Factors↗
PubMed1992

8-Hydroxy-2-(di-n-propylamino)tetralin, a 5-HT1A receptor agonist, impairs performance in a passive avoidance task.

The effects of various subcutaneous doses (30, 100 and 300 micrograms/kg) of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a serotonin (5-HT)1A receptor agonist, were studied on the performance of rats in a one-trial passive avoidance task. When administered 30 min before the training trial and the retention test, 8-OH-DPAT significantly reduced retention latencies at all doses. Similar results were obtained when 8-OH-DPAT was administered before either the training trial or the retention test. When administered 5 min after the training trial, 100 and 300 micrograms/kg 8-OH-DPAT significantly reduced the retention latencies whereas 30 micrograms/kg caused a non-significant tendency to a reduction. A dose of 300 micrograms/kg 8-OH-DPAT significantly raised the thresholds for various responses (flinch, jump and vocalization) elicited by electric shock applied to the grid floor while 30 and 100 micrograms/kg had no effect. When administered 30 min before the retention test to rats that could choose between a punished and unpunished compartment, 8-OH-DPAT at 100 and 300 micrograms/kg facilitated re-entry to either compartment but, like control animals, most 8-OH-DPAT-treated animals preferred the unpunished compartment. Although the effects of 8-OH-DPAT on pain perception, general activity or emotional behavior may interfere with the performance of rats in the passive avoidance task, the results suggest that at 100 and 300 micrograms/kg 8-OH-DPAT interferes with mechanisms related to the acquisition and consolidation of memory.

5,7-Dihydroxytryptamine↗
PubMed1992

Metastatic rhabdomyosarcoma and histologically similar tumors in childhood: a retrospective European multi-center analysis.

This is a retrospective analysis of children with metastatic soft tissue sarcoma (STS) registered in the major European STS studies: the SIOP MMT 75, the German CWS 1981 and 1986 studies, the Italian STS study, and the United Kingdom Children's Cancer Study Group centres in Britain. One hundred forty-six patients out of 164 were evaluable in this analysis. The median age was 7 years (1-18) and the male/female ratio was 1.3:1. The median follow-up was 80 months (7-171). The most common site of the primary tumor was the extremity (28%), which correlated well with the high preponderance (39%) of the alveolar type of RMS (aRMS). There was no dominant combination of metastatic sites and the most common single organ with metastasis was the lung (41%). Since the therapy depended on the country and period in which the patient was treated, we did not analyse the outcome and therapy together. Complete remission was achieved in 50% of the cases. Those with aRMS had a good chance of achieving CR (61%) but the majority of these patients relapsed (78%). The median time needed to relapse was 243 days (53 days to 47 months) for all patients. Analysis of the site of the primary tumor showed that the CR rate was best in the GU non-BP site (62%) and worst in PM cases (35%). The overall survival and DFS rate were 18% and 15%, respectively. The GU non-BP patients had a DFS rate of 50%, while the rate for all other sites varied between 12% and 18%. A total of 24 patients remained in CCR. The majority of them had embryonal type of RMS and metastases in only one anatomic site. Our analysis indicates that the best chance of prolonged survival was in metastatic GU non-BP cases, patients with embryonal type RMS, and those with metastases in only one organ. To try to improve the treatment of metastatic STS, a prospective European cooperative study was started in 1989.

Adolescent↗
PubMed1992

Serotonin2 receptor agonists and serotonergic anorectic drugs affect rats' performance differently in a five-choice serial reaction time task.

A five-choice serial reaction time task was used to study the effects of serotonin (5-HT) receptor agonists and antagonists on accuracy of performance and food-motivated behaviour. Lysergic acid diethylamide (LSD), 0.1 mg/kg IP and quipazine, 2.5 mg/kg IP significantly reduced the percentage of correct responses and increased the percentage of omissions with no effect on other measures such as latency to collect the reinforcement or to respond correctly. The effects of LSD and quipazine were reversed by 1-2 mg/kg ritanserin, a potent 5-HT2 and 5-HT1C receptor antagonist. Metachlorophenylpiperazine (mCPP) 2.5 mg/kg IP, an agonist at 5-HT1B and 5-HT1C receptors, and d-fenfluramine (DF) 1.25 mg/kg IP, a releaser of 5-HT from nerve terminals and inhibitor of 5-HT uptake, increased the percentage of omissions and the latency to respond correctly or to collect the reinforcement with no effects on the correct responses. Effects similar to those of mCPP and DF were obtained by 60 min access to food before testing. Haloperidol, 0.1 mg/kg IP, did not affect the percentage of correct responses or the latency to collect the reinforcement, but significantly increased the proportion of errors of omission and the latency to respond correctly. The results show that 5-HT2 receptor agonists cause attentional disturbances at doses that have no marked effect on motivation for food or speed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Spindle cell rhabdomyosarcoma. A prognostically favorable variant of rhabdomyosarcoma.

Twenty-one cases of embryonal rhabdomyosarcoma, composed mainly of elongated spindle cells arranged in a fasciculated or storiform pattern, were retrieved from the files of the German-Italian Cooperative Soft Tissue Sarcoma Study. The term spindle cell rhabdomyosarcoma is proposed to designate this histotype. Spindle cell rhabdomyosarcoma predilected male patients (18 males, three females) and involved mostly the paratesticular area (12 cases) and the head and neck region (six cases). Histologically, all cases were characterized by a uniform proliferation of elongated spindle cells with eosinophilic and fibrillar cytoplasm mimicking smooth muscle fibers; immunocytochemical studies disclosed high expression of the muscle markers titin, desmin, and myoglobin. Clinical information was available in 17 cases; according to the Intergroup Rhabdomyosarcoma Study (IRS) grouping system, 13 were classified in group I, two in group II, and two in group III. Sixteen patients were well and alive 24 to 100 months after diagnosis; one patient died from disease progression 24 months after diagnosis. Analysis of our results determined that spindle cell rhabdomyosarcoma constitutes a rare variant of the embryonal form, showing a high degree of skeletal muscle differentiation and a low malignant potential; it should therefore be distinguished from classical forms of embryonal rhabdomyosarcoma.

Adolescent↗
PubMed1992

[3H]paroxetine binding and serotonin content of rat cortical areas, hippocampus, neostriatum, ventral mesencephalic tegmentum, and midbrain raphe nuclei region following p-chlorophenylalanine and p-chloroamphetamine treatment.

The agents p-chlorophenylalanine (PCPA) and p-chloroamphetamine (PCA) deplete brain serotonin (5-HT) levels by two different mechanisms; PCPA inhibits the enzyme tryptophan hydroxylase, whereas PCA has a neurotoxic action on certain 5-HT neurons. The parameters of [3H]paroxetine binding to homogenates prepared from the cerebral cortex of rats treated with PCPA, PCA, or saline; vehicle were investigated. The tissue concentrations of 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) were also determined by HPLC in the same brain samples. After PCPA treatment, neither the maximum binding capacity (Bmax) nor the dissociation constant (KD) of [3H]paroxetine for the 5-HT uptake recognition site differed from controls despite a substantial reduction in the concentration of 5-HT and 5-HIAA. In contrast, significant changes in both the Bmax and KD values were observed in the cerebral cortex of rats treated with PCA. Furthermore, [3H]paroxetine binding and tissue concentrations of 5-HT and 5-HIAA were measured in the following different regions of the rat brain: cingulate, parietal, and visual cortical areas; dorsal and ventral hippocampus; rostral and caudal halves of neostriatum; ventral mesencephalic tegmentum; and midbrain raphe nuclei region after administration of PCPA, PCA, or saline vehicle. There was an excellent correlation between regional 5-HT levels and specific [3H]paroxetine binding in control and PCA-treated rats although this correlation was lost after PCPA treatment. Under these conditions, the 5-HT innervation remains unchanged whereas the concentration of 5-HT and 5-HIAA is greatly reduced. Thus, [3H]paroxetine binding appears to provide a reliable marker of 5-HT innervation density within the mammalian CNS.

Animals↗
PubMed1992

8-Hydroxy-2-(di-n-propylamino)tetralin impairs spatial learning in a water maze: role of postsynaptic 5-HT1A receptors.

1. The effects of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A receptor agonist, on place navigation was studied by use of two spatial tasks in a water maze. 2. In the first experiment, rats treated subcutaneously with 100 and 300 (but not 30) micrograms kg-1 8-OH-DPAT were impaired in their ability to locate a hidden platform. The probe test confirmed the impairment of spatial navigation but the effect (time spent in the training quadrant) was quantitatively different, depending on whether 8-OH-DPAT was administered only before each training session, only before the probe test or in both conditions. 3. In the second experiment, rats received 150 micrograms 5,7-dihydroxytryptamine (5,7-DHT) intracerebroventricularly to destroy 5-hydroxytryptamine (5-HT)-containing neurones and 24 days later were examined for choice accuracy in a two-platform spatial discrimination task. 4. At 100 (but not 30) micrograms kg-1 8-OH-DPAT impaired rats' accuracy with no effect on latency and no errors of omission. In 5,7-DHT-treated rats, this dose had a greater effect, including errors of omission. Sham-operated rats injected with 300 micrograms kg-1 8-OH-DPAT were markedly impaired in accuracy but they had longer latencies and made more errors than controls. All the effects were increased in 5,7-DHT treated rats. 5. The results suggest that, at doses causing no apparent changes in motor behaviour or motivation, 8-OH-DPAT impairs spatial navigation by stimulating postsynaptic 5-HT1A receptors in the rat brain.

5,7-Dihydroxytryptamine↗
PubMed1992

Standard-dose and high-dose peptichemio and cisplatin in children with disseminated poor-risk neuroblastoma: two studies by the Italian Cooperative Group for Neuroblastoma.

PURPOSE: The objective of the present study was to determine whether an increase in the intensity of therapy improves outcome for children with disseminated poor-risk neuroblastoma. PATIENTS AND METHODS: From January 1982 through November 1989, 181 children 1 year or older with newly diagnosed disseminated neuroblastoma were entered onto two consecutive studies of the Italian Cooperative Group for Neuroblastoma (ICGNB): 75 (study NB82) were enrolled from 1982 to 1984 and were treated with standard-dose (SD) chemotherapy, and 106 (study NB85) were enrolled from 1985 to 1989 and received high-dose (HD) chemotherapy. In both treatment protocols, induction therapy included peptichemio and cisplatin (at SD or HD, respectively) and removal of the primary tumor. In study NB82, children who achieved complete or partial tumor regression received SD consolidation therapy, and in study NB85 they received three cycles of HD chemotherapy (3cCT) or one cycle of myeloablative therapy (MAT) followed by autologous bone marrow transplantation (ABMT). RESULTS: Compared with group NB82, the NB85 group had significantly fewer failures (no tumor response or disease progression) after administration of peptichemio (9% v 31%; P < .01), had more complete responses (CRs) and partial responses (PRs) both after treatment with cisplatin (60% v 43%; P = .01) and after surgery (76% v 57%; P < .01), and was more likely to have achieved complete excision of the primary tumor (70% v 46%; P < .01). Overall survival (OS) and progression-free survival (PFS) at 5 years were 11% and 9% in NB82, and 27% and 18% in NB85 (P < .01 for both); however, in NB85, relapses occurred even after 5 years of CR, so that PFS curves converge approximately 7 years after diagnosis. Median survival time was 14 months in NB82 and 24 months in NB85. Children in the NB85 group who after achievement of CR were consolidated with 3cCT had a 5-year PFS of 24% compared with 32% of those treated with MAT followed by ABMT (P = .5). CONCLUSION: Intensified therapy improves response rate and prolongs survival of children with disseminated neuroblastoma, although its impact on the eventual cure rate remains to be established.

Adolescent↗
PubMed1991

Prognostic factors in 951 nonmetastatic rhabdomyosarcoma in children: a report from the International Rhabdomyosarcoma Workshop.

A total of 951 newly diagnosed patients with nonmetastatic rhabdomyosarcoma (RMS) under 21 years of age from four different cooperative study groups were analyzed to identify the most important pretreatment tumor characteristics in predicting survival. The patient characteristics considered were tumor invasiveness (T), tumor size, status of locoregional lymph nodes, and primary site. The cooperative groups and studies analyzed were: SIOP [RMS-75 (1975-1984)], the Intergroup Rhabdomyosarcoma Study [IRS-II (1978-1982)], Federal Republic of Germany [CWS-81 (1981-1986)] and Italy [RMS-79 (1979-1986), each study involving a different therapeutic protocol. Patient characteristics identified as having a significant relationship to survival by univariate analysis were (favorable features given in brackets): tumor invasiveness [T1], tumor size [less than or equal to 5 cm], status of locoregional lymph nodes [clinically negative], and primary site [orbit and genitourinary non-bladder prostate (GU-non-BP) sites]. T2 tumors tended to have large size (greater than 5 cm), to be associated with positive nodes, and to have a different distribution by primary site than T1 tumors. A multivariate Cox regression analysis of the pooled data identified tumor invasiveness (T), primary site, and the interaction between T and primary site as significant predictive factors for survival. The prognosis of orbital tumors was consistently favorable regardless of T status, whereas the prognosis for "other sites" was consistently unfavorable. International cooperation in this study has permitted the identification of good and poor risk patient subgroups, permitting the focusing of therapeutic protocols to particular risk groups and setting the stage for common future therapeutic protocols for rare subgroups of patients.

Child↗
PubMed1991

Administration of 8-hydroxy-2-(Di-n-propylamino)tetralin in raphe nuclei dorsalis and medianus reduces serotonin synthesis in the rat brain: differences in potency and regional sensitivity.

Following administration of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.04-5.0 micrograms/0.5 microliter) in the raphe nucleus dorsalis (DR) or medianus (MR), the synthesis of serotonin (5-HT), as assessed by the accumulation of 5-hydroxytryptophan (5-HTP) after decarboxylase inhibition, was measured in various regions of the rat CNS. At all doses, 8-OH-DPAT in the DR significantly reduced 5-HTP accumulation in the striatum, nucleus accumbens, cortex, and prefrontal cortex, whereas even the highest dose had no effect in the hippocampus, hypothalamus, and spinal cord. One microgram of 8-OH-DPAT in the MR significantly reduced 5-HTP accumulation in the nucleus accumbens and prefrontal cortex, and 5 micrograms had an effect in all the areas except the striatum and spinal cord. One and 5 micrograms of 8-OH-DPAT, administered in either the DR or MR, did not significantly modify the accumulation of dihydroxyphenylalanine in the striatum and nucleus accumbens. The results confirm that DR and MR have different sensitivities to 5-HT1A receptor agonists, and that activation of 5-HT1A receptors in these nuclei produces different effects on 5-HT synthesis in different brain regions.

5-Hydroxytryptophan↗
PubMed1991

[Multicenter retrospective study of 3,024 patients operated on for stomach cancer in Italy. Epidemiology, surgical treatment and survival].

This study presents the results achieved in 2,000 patients who underwent gastric resection and who had been selected from amongst 3,074 cases of gastric neoplasia included in the Retrospective Study of Carcinoma of the Stomach, carried out by the "Italian Stomach Cancer Group" of the Association of Italian Hospital Surgeons (ACOI). In terms of the UICC TNM classification, these patients consisted of 234 stage I patients, 494 stage II patients 1,011 stage III patients and 261 stage IV patients. The overall operative mortality was 7.1 percent. This was lower after subtotal distal resection. The long-term survival tended to fall in proportion with the stage of the illness, whereas the degree of the exeresis did not appear to have any impact. The overall survival at 5 years in the patients who survived the operation was 45%, that following distal resection was 54% and that after total gastrectomy was 33%. The survival rate in terms of the stage ranged from 86% for Early Gastric Cancers to 28% for the patients who underwent surgery at stage III i.e. when they had metastatic lymph nodes.

Adult↗
PubMed1990

Wilm's tumor with pulmonary metastases at diagnosis: the significance of primary chemotherapy. International Society of Pediatric Oncology Nephroblastoma Trial and Study Committee.

Data from patients with pulmonary metastases (PM) from Wilms' tumor at diagnosis (stage IV) were collected from six European centers. All patients were pretreated with a chemotherapy (CT) regimen consisting of vincristine (VCR), dactinomycin (AD), and Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH). After nephrectomy, local therapy for residual pulmonary disease was considered to avoid whole-lung irradiation. Only four of 36 patients still had multiple inoperable metastases after preoperative CT. Thirty patients survived. Four of them were irradiated. Of the six patients who died, four died of PM, one died of abdominal recurrence, and one of therapy-related disease. Disease-free survival and actuarial survival rates are 83% with a mean follow-up of 4 years postnephrectomy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Risk factors for soft tissue sarcomas in childhood: a case-control study.

A hospital-based case-control study on soft tissue sarcomas (STS) was conducted in 1983-84 in Torino and in Padova (Italy). Cases (36 children with rhabdomyosarcoma (RMS) and 16 non RMS-STS) were compared to 326 controls. Histories of parental smoking habits and occupations, parental and children's exposure to ionizing radiation, children's diseases and some other variables were collected through interviews to the relatives attending the child in the hospital. A non statistically significant association was observed with both maternal age above 30 at child's birth (STS: OR = 1.5, C.I. = 0.8-2.9; RMS: OR = 1.9, C.I. = 0.9-4.0) and "in utero" exposure to diagnostic radiation (STS: OR = 1.9, C.I. = 0.5-6.5, based on 4 cases). No association was found with children's previous diseases. Paternal and maternal smoking habits were similar for RMS and STS cases and controls. Some positive associations with either maternal or paternal occupational histories were identified. They are difficult to interpret in view of the large number of comparisons and small absolute figures. They included maternal employment as medical doctor and nurse, farmer, textile worker and machine tool operator. An association was also observed with paternal occupation as butcher, building worker or employment in the production of domestic appliances. One case and no controls reported a maternal aunt affected by breast cancer.

Case-Control Studies↗
PubMed1989

Effect of 5-HT1A agonists on stress-induced deficit in open field locomotor activity of rats: evidence that this model identifies anxiolytic-like activity.

Deficits in locomotion and exploratory behaviour in an open field were induced in rats by restraint for 2 hr, 23 hr before testing. Diazepam, 0.62 and 1.25 mg/kg, intraperitoneally (i.p.), 15 min before testing, reversed the stress-induced reduction in locomotion; 1.25 mg/kg also attenuated the effect of stress on exploration (rearing and object exploring). Diazepam did not affect the activity of controls. A putative anxiogenic compound, pyrazoloquinoline (CGS 8216, 10 mg/kg administered 30 min before testing), also markedly reduced locomotion and exploration and the effect was reversed by 2.5 mg/kg diazepam, 15 min before testing. Buspirone, 0.1 mg/kg subcutaneously (s.c.) 15 min before testing, significantly attenuated the effect of stress on locomotion and exploration but had no effect in controls. Larger doses (0.5 and 1.0 mg/kg) markedly reduced the behavioural measures in controls and did not modify or enhance the effect of stress. 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), 0.25 and 0.5 mg/kg (s.c.), 1 hr before testing, significantly attenuated the reduction in locomotion without affecting rearing and object-exploring in stressed rats. At doses from 0.125 to 0.5 mg/kg, 8-OH-DPAT reduced exploration in control rats. Two hr after restraint (corresponding to 21 hr before testing in the open field) 8-OH-DPAT, 0.125 to 2 mg/kg (s.c.), did not modify the open field deficits, caused by stress. In these treatment conditions, 0.5 and 2 mg/kg 8-OH-DPAT reduced locomotion and exploration in control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗