Adenosine A2 receptors stimulate c-fos expression in striatal neurons of 6-hydroxydopamine-lesioned rats

The induction of the early-gene c-fos after administration of the adenosine A2a receptor agonist CGS 21680, was studied in the striatum of normal rats or in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal neurons. CGS 21680 (2.25 mg/kg) induces c-fos expression in the 6-hydroxydopamine-lesioned striatum, while up to 40 mg/kg fails to induce c-fos in the intact striatum or in the striatum of normal rats. Blockade of muscarine receptors by scopolamine (5 mg/kg) partially prevents, and stimulation of dopamine D2 receptors by quinpirole (0.5 mg/kg) completely reverses, CGS 21680-induced c-fos expression in the 6-hydroxydopamine-lesioned striatum. In turn, CGS 21680 partially reverses c-fos expression induced by quinpirole in the lesioned globus pallidus. CGS 21680, in addition, dose-dependently reduces the turning behavior induced by quinpirole (0.5 mg/kg) in 6-hydroxydopamine-lesioned rats. The results suggest that CGS 21680 induces c-fos expression in the striatum through direct and indirect mechanisms related to the ability of A2a receptors to stimulate cyclic AMP formation or acetylcholine release which in turn would activate c-fos through muscarinic receptors.

Modulation of dopamine D1-mediated turning behavior and striatal c-fos expression by the substantia nigra

In order to study the possible contribution of the substantia nigra (SN) in the positive interaction between dopamine D1 receptor agonists and glutamate antagonists in unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats, the effect of the D1 agonist, SKF 38393, was studied in combination with intranigral infusions of glutamate antagonists of the NMDA (MK 801, CPP) or AMPA (NBQX) type of receptor. Local infusion into the SN of the 6-OHDA lesioned side of MK 801, CPP or NBQX at doses inducing no or minimal behavioral effects significantly increased the turning behavior and the expression of c-fos induced, in the lesioned caudate-putamen (CPu), by a parenteral administration of SKF 38393. The same result was obtained after intra-SN infusion of the GABA agonist, muscimol. High doses of MK 801, CPP or muscimol infused into the SN produced intense contralateral turning per se and induced a sparse c-fos expression in the lesioned CPu which was antagonized by parenteral administration of MK 801. The results indicate that a depression of SN pars reticulata efferent neurons potentiates D1-mediated responses and suggest that this area may play a role in the positive interaction between glutamate antagonists and D1 receptor agonists.

Benefits and complications of laparoscopic pelvic lymphadenectomy for detection of stage D1 prostate cancer: a multicenter experience

One hundred fifty-eight consecutive patients with clinically localized prostate cancer were submitted to staging laparoscopic pelvic lymphadenectomy (LPL) at 5 cooperative centers with one or more of the following conditions which were considered as risk factors for nodal disease: clinical stage C (or T3) disease, serum prostate-specific antigen > 20 ng/ml, Gleason sum > 6. The mean number of lymph nodes removed was 11 (range 2-29). Metastases from prostate cancer were found in 41 patients (25.9%). The proportion of lymph node-positive patients increases significantly with the presence of one, two or three of the conditions considered as risk factors (p < 0.00005). The benefit of LPL is limited to the lymph node-positive patients who can be spared a second operation.

Differential effect of MK 801 and scopolamine on c-fos expression induced by L-dopa in the striatum of 6-hydroxydopamine lesioned rats

In rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigro-striatal pathway, striatal D1-receptor-stimulated c-fos expression and turning behavior are positively modulated by D2 receptor stimulation and by blockade of N-methyl-D-aspartate (NMDA) or muscarinic receptors. Combined D1/D2 receptor stimulation by L-dopa activates c-fos in a manner not additive with muscarinic receptor blockade by scopolamine. On the other hand, blockade of NMDA receptors by MK 801 reduced c-fos expression induced by L-dopa while, depending on the dose of L-dopa, differentially affecting contralateral turning behavior. The results are interpreted to suggest that D2 receptor stimulation amplifies D1-receptor-mediated c-fos expression by two mechanisms differentially related to muscarinic and NMDA receptors.

[Aarskog syndrome. A case report]

A case of Aarskog syndrome in a 10-year-old boy born to an epileptic woman is reported. Clinical features and genetics of the condition are reviewed. An underestimated incidence of the syndrome related to its mild phenotypical appearance is suggested. Finally the association between Aarskog syndrome and maternal epilepsy is discussed.

Behavioural sensitization in 6-hydroxydopamine lesioned rats involves the dopamine signal transduction: changes in DARPP-32 phosphorylation

"Priming" is a phenomenon of behavioural sensitization observed in unilaterally 6-hydroxydopamine lesioned rats following exposure to a dopamine agonist. After priming, a single dose of the D1 agonist SKF 38393 (3 mg/kg) produces contralateral turning, while the same dose is inactive in drug-naive, lesioned animals. The molecular mechanisms of "priming" were investigated here by studying the phosphorylation of dopamine and adenosine 3'-5' monophosphate regulated phosphoprotein (DARPP-32), a dopamine- and cyclic AMP-regulated phosphoprotein functionally linked to D1 receptors in striatum. Dephospho-form of DARPP-32 were measured by a back-phosphorylation assay. All assays were performed in striata from both lesioned and unlesioned sides. A significant decrease of dephospho-DARPP-32 (27%) was observed in the denervated striatum of primed rats, indicating an increased phosphorylation in vivo of DARPP-32 in response to the D1 agonist. The levels of DARPP-32 protein, as measured by quantitative immunoblotting, remained unchanged in all experimental groups. This study shows that priming is expressed as an increased transduction of the D1 receptor message.

Modulatory functions of neurotransmitters in the striatum: ACh/dopamine/NMDA interactions

The striatum is viewed as a structure performing fast neurotransmitter-mediated operations through somatotopically organized projections to medium-size spiny neurons. This view is contrasted with another view that depicts the striatum as a site of diffuse modulatory influences mediated by cholinergic interneurons and by dopamine and N-methyl-D-aspartate receptors. These two operational and organizational modes both contribute, through their mutual interaction, to the function of basal ganglia. Detailed knowledge of the neural mechanisms by which such interactions take place and are expressed into behaviour, can provide new insight into the physiopathology and new clues for therapy of disorders of basal ganglia.

Adenosine A2 receptors interact negatively with dopamine D1 and D2 receptors in unilaterally 6-hydroxydopamine-lesioned rats

In rats bearing a unilateral 6-hydroxydopamine lesion of the dopaminergic nigro-striatal pathway, stimulation of adenosine A2 receptors by CGS 21680 reduced the contralateral turning behavior induced by L-3,4-dihydroxyphenylalanine (L-DOPA). Administration of CGS 21680 completely blocked the contralateral turning induced by the dopamine D1 receptor agonist, SKF 38393, and reduced the turning induced by the dopamine D2 receptor agonist, LY 171555. Quinolinic acid lesion of the striatum or 6-hydroxydopamine lesion of the dopaminergic nigro-striatal neurons demonstrated that [3H]CGS 21680 binding sites are associated to striatal intrinsic neurons. This study provides evidence for a negative postsynaptic interaction of both dopamine D1 and D2 receptors with adenosine A2 receptors.

L-dopa stimulates c-fos expression in dopamine denervated striatum by combined activation of D-1 and D-2 receptors

Administration of L-dopa to unilaterally 6-hydroxydopamine-lesioned rats, activates the early gene c-fos in the lesioned caudate-putamen. D-1 receptor blockade by SCH 23390, prevented L-dopa-induced Fos-like immunoreactivity in the whole caudate-putamen, while D-2 receptor blockade by raclopride reduced Fos-like immunoreactivity only in the dorso-lateral portion. The results suggest that L-dopa induces c-fos primarily through an activation of D-1 receptors, while D-2 receptor stimulation plays a facilitatory influence on D-1-mediated c-fos expression.

Stimulation of dopamine transmission in the dorsal caudate nucleus by pargyline as demonstrated by dopamine and acetylcholine microdialysis and Fos immunohistochemistry

The effect of pargyline on dopamine neurotransmission was investigated by trans-striatal microdialysis combined with Fos immunohistochemistry. Pargyline, 75 mg/kg i.p., increased dopamine and acetylcholine output while drastically decreased dopamine deaminated metabolites. Administration of pargyline resulted in the appearance of Fos-positive nuclei distributed along a gradient around the dialysis probe. Pretreatment with the D1 antagonist SCH 23390 potentiated the effect of pargyline on dopamine output while preventing that on acetylcholine output and on Fos formation. Similarly, lack of calcium in the perfusion medium abolished the effect of pargyline on dopamine and acetylcholine output and on Fos formation. In rats not implanted with dialysis probes pargyline administration resulted in only rare Fos-positive nuclei in the dorsal caudate. The present study indicates that pargyline stimulates dopamine transmission in the dorsal caudate in the area around the dialysis probe but not distant from the fibre or in unimplanted rats. This effect appears to reflect an interaction between the drug-induced changes and those locally elicited by the probe.

Creatine-kinase isoenzyme pattern in colonic infarction consequent to acute aortic dissection. A case report

Bowel infarction can complicate acute aortic dissection (AAD); in that case early diagnosis, which decreases the high mortality, is often difficult. We report the case of one patient who underwent surgery for AAD and developed a colonic infarction, which was clinically manifest on the 4th postoperative day. However, bowel ischemia was suspected already 48 hours after surgery, on the basis of the suggestive CK pattern and the absence of myoglobin in plasma. Total CK activity reached the highest level only 48 hours after surgery (92,800 U/l); the peak was coincident with LDH, which increased proportionally less; CK-MM constituted 100% of total CK activity. The absence of myoglobin in plasma excluded the presence of rhabdomyolysis. We conclude that such laboratory findings suggest the occurrence of severe bowel ischemia.

Expression of c-fos protein in the experimental epilepsy induced by pilocarpine

The expression of the c-fos proto-oncogene, as estimated by immunohistochemistry of the FOS nuclear protein, was studied in both focal and generalized seizures induced in rats by systemic administration of pilocarpine. Focal seizures, as indicated by the occurrence of stereotyped oral movements, chewing and sniffing, were evoked by either a subconvulsant dose of pilocarpine (200 mg/kg) or the association of a convulsant dose of pilocarpine (400 mg/kg) with SCH 23390, a selective D-1 dopamine receptor antagonist. This seizure pattern resulted in FOS accumulation in certain limbic areas, namely, the piriform cortex, amygdala, and olfactory tubercle. On the other hand, in rats developing generalized seizures, accumulation of FOS was also found in hippocampus, cingulate cortex, frontal cortex, striatum, accumbens, as well as in certain thalamic nuclei. Generalized seizures, including motor limbic seizures and status epilepticus, were induced by either a convulsant dose of pilocarpine (400 mg/kg) or a low dose of pilocarpine (15-200 mg/kg) combined with either lithium or the D-1 selective agonist SKF 38393. These findings indicate a close correlation between the sequence of behavioural alterations induced by pilocarpine and the proto-oncogene activation. The results provide the basis for mapping the areas of origin and the pathways of generalization of seizure activity. As shown by the effects of dopamine receptor agonists and antagonists, the process of generalization appears to be controlled by the dopamine system.

Blockade of muscarinic receptors potentiates D1 dependent turning behavior and c-fos expression in 6-hydroxydopamine-lesioned rats but does not influence D2 mediated responses

In rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal pathway, blockade of muscarinic receptors by scopolamine potentiates the contralateral turning induced by selective dopaminergic D1 agonists (SKF 38393, A 68930), but does not influence the contralateral turning induced by the D2 agonist LY 171555. Studies on the expression of the early gene c-fos as reflected by the immunohistochemical demonstration of the Fos protein, show that administration of scopolamine (5 mg/kg, i.p.) potentiates c-fos expression elicited by SKF 38393 (1.5 mg/kg, s.c.) in the caudate-putamen of the lesioned side. The results indicate that cholinergic transmission is differentially involved in the behavioral expression of D1 versus D2 receptor stimulation in a denervated condition and suggest that blockade of central cholinergic transmission might be useful in improving the antiparkinsonian efficacy of D1 receptor agonists.

Local cerebral glucose utilization after D1 receptor stimulation in 6-OHDA lesioned rats: effect of sensitization (priming) with a dopaminergic agonist

In rats bearing unilateral 6-hydroxydopamine (6-OHDA) lesions of the dopaminergic nigro-striatal neurons, a single administration of a D-2 agonist (LY 17155) potentiates the contralateral turning induced by a D-1 agonist (SKF 38393). To identify the neural substrate of this form of sensitization (priming), we studied the local cerebral glucose utilization (lCMRglc) in 6-OHDA lesioned animals treated, 3 days apart, as follows: (1) saline-saline, (2) LY 171555-saline, (3) saline-SKF 38393 and (4) LY 171555-SKF 38393. The unilateral 6-OHDA lesion per se (Sal-Sal) produced increases in lCMRglc in the globus pallidus (GP) and in the lateral habenula (LH) of the lesioned hemisphere. lCMRglc in LY-Sal group were similar to those measured in the Sal-Sal group. Administration of SKF 38393 to drug-naïve rats (Sal-SKF) abolished the lesion-induced metabolic asymmetry in the LH but did not have any effect on the GP; furthermore, it increased lCMRglc in the substantia nigra pars reticulata (SNr) of the lesioned side. After priming with LY 171555, administration of SKF 38393 (LY-SKF) produced marked metabolic asymmetries by increasing lCMRglc in the SNr and entopeduncular nucleus (EP), and decreasing it in the LH of the lesioned side. These changes were also significant when compared to the corresponding values of the other experimental groups. Again, in LY-SKF group no modification of the lesion-induced metabolic asymmetry in the GP was found.(ABSTRACT TRUNCATED AT 250 WORDS)

[Liver injury in abdominal trauma. Review of the literature and personal observations]

In patients who suffered abdominal trauma, the liver is the most frequently involved organ, except the spleen. The % rises from 1520% to 30% if trauma is closed or open. Liver injury may spread from a simple parenchymal contusion to a break in vessels or biliary ducts. Life risk is related to hemorrhage. The mortality is due to: 1) extension of the injured liver surface, 2) possible damage to big vessels, 3) intra or extra abdominal associated injury in case of multiple trauma. It is important to known the kind of injury to choose the best therapy, not necessary surgical. The authors report on 15 patients with thoracoabdominal trauma and liver damage, comparing their cases with literature observations.

Metabolic mapping of the synergism between MK-801 and SKF 38393 in rats with unilateral lesions of the dopaminergic nigrostriatal pathway

In rats with a unilateral lesion of the dopaminergic nigrostriatal pathway with 6-hydroxydopamine, blockade of N-methyl-D-aspartate receptors by MK-801 strongly potentiated the turning behavior induced by D-1 receptor stimulation. To determine the functional consequences of such positive interaction we measured the local rates of cerebral glucose utilization (lCMRglc) in lesioned rats treated with MK-801 (0.1 mg/kg) and the D-1 agonist SKF 38393 (1.5 mg/kg), either alone or in combination. Treatment with each drug separately did not induce any substantial change in lCMRglc besides an increase in the metabolic activity of the dorsomedial caudate and entopeduncular nucleus (EP) of the lesioned side of MK-801 treated rats, as compared to the same side of lesioned rats treated with vehicle. Combined administration of MK-801 + SKF 38393 increased lCMRglc in the EP (+77%) and in the substantia nigra pars reticulata (SNr) (+30%) of the lesioned side as compared with the intact side, while it decreased lCMRglc in the lateral habenula (-26%). These changes were also significant when compared to the lesioned side of vehicle treated rats. The results suggest that while the caudate putamen might be the primary site of MK-801 and SKF 38393 positive interaction, the EP and SNr are the striatal efferent areas where this positive interaction is expressed.

[Respiratory inductive plethysmography in the functional evaluation of patients undergoing coronary by-pass surgery]

The functional respiratory changes following coronary by-pass surgery were previously evaluated with the traditional spirometric method. Aim of this work is to introduce the respiratory inductive plethismography (RIP), a well known non-invasive technique, into the study of those volumetric and ventilatory modifications. Eight cardioischemic patients were selected: all but one were free from pulmonary disorders. The tidal volume, the respiratory rate, the minute ventilation, the vital capacity and the relation between the abdominal and the thoracic part of the ventilatory act, were measured in the pre-intervention session and in the 1st, 3rd and 7th day after the operation of coronary by-pass. In the same sessions, except the 1st day after surgery, the maximal respiratory pressures were evaluated with traditional manometers. The functional changes of the examined parameters, statistically studied with the variance analysis, closely resemble the spirometric modifications registered by other authors. Furthermore the relative contributions of the thoracic and abdominal compartments of the pulmonary ventilation were evaluated, thanks to the non-invasive plethysmographic method. Rip makes it possible to measure the ventilatory pattern and some pulmonary volumes in the very early phases after thoracic surgery, without any trouble for the patient and in a non-collaborative state of consciousness, too.

Localization of MPP+ binding sites in the brain of various mammalian species

The distribution and density of 3H-MPP+ binding sites were studied by in vitro quantitative autoradiography in the brain of the mouse, rat and monkey. The highest levels of 3H-MPP+ specific binding were observed in rat brain. The substantia nigra in rat and monkey, and the anterior caudate-putamen formation in mouse and monkey showed the lowest density of autoradiographic grains. The presence of a relatively high density of MPP+ sites in the hippocampus of all species studied could be of interest to explain some effects of MPTP administration on convulsions caused by chemoconvulsants. The finding of a 60-70% reduction of 3H-MPP+ binding sites in the rat caudate-putamen, on the side of quinolinic acid infusion and no changes after 6-hydroxydopamine lesion of dopaminergic nigrostriatal neurons suggests the presence of these sites mainly on striatal cells. The results suggest that the distribution of MPP+ binding sites in brain would not seem to be related to MPTP toxicity.

Combined microdialysis and Fos immunohistochemistry for the estimation of dopamine neurotransmission in the rat caudate-putamen

Extracellular dopamine (DA) concentrations estimated by transcerebral dialysis and D1-dependent c-fos expression, as demonstrated by Fos immunohistochemistry, were studied after blockade of DA reuptake by GBR-12909. Rats implanted with dialysis probes in the dorsal caudate-putamen did not show any Fos-positive neuronal labeling in the implanted area or in the rest of the caudate-putamen. Administration of GBR-12909 dose-dependently increased DA output in dialysates and resulted in the appearance in the caudate-putamen of Fos-positive neurons whose density was related to the dose of GBR-12909 and to the increase in extracellular concentrations of DA. The D1 antagonist SCH-23390 blocked GBR-12909-induced activation of Fos while potentiating the stimulation of DA output. The results show that following blockade of DA reuptake by GBR-12909, the induction of Fos is related to stimulation of D1 receptors by extracellular DA. Combination of brain dialysis with Fos immunohistochemistry might provide a method for estimating the functional significance of extracellular DA as measured by brain microdialysis.

[A case of intestinal occlusion caused by malignant ileal lymphoma]

The Authors review a case of intestinal non-Hodgkin lymphoma, whose clinical feature was an intestinal obstruction caused by ileoileal intussusception. Some findings which make it unusual are compared with those mentioned in the international literature.

[Loco-regional analgesia with continuous peridural technique in labor. Evaluation of 4 years of experience]

The Authors report on the results of their experience using local-regional analgesia performed with the continuous peridural technique over four years of activity with 503 pregnant women. Protocols used over the years called for morphine-fentanyl association, but bupivacaine 0.25% plus fentanyl and bupivacaine 0.125% plus fentanyl mixtures were then employed. In order to evaluate the efficiency of this procedure, the following data were recorded for each patient undergoing the analgesia: duration of labor prior to the effect of the analgesia; time to reach complete dilatation from a 3 cm dilatation; the length of time of the expulsive phase; manifestation of side effects and complications; vacuum utilization. Furthermore, Apgar scores were taken for all newborn babies at 1st and 5th minutes. The data were then compared with those recorded for a group of women with the same obstetrical characteristics who were not treated with analgesia. The comparison showed that the length of time of the dilatation phase (from 3 to 10 cms) was significantly less in the group of treated patients, while the expulsive phase was basically similar in both groups, thus showing that labor mean time had significantly decreased in the group of patients treated with analgesia. The number of vacuum births was basically the same in both groups and comparable to the data available in the literature. These were practically no side effects or complications. In conclusion, our experience confirms the fact that this method is the most reliable in terms of safety, effectiveness and acceptability on the part of women compared to any other analgesic treatment employed during labor.

Blockade of N-methyl-D-aspartate receptors potentiates dopaminergic responses in the 6-OHDA model of parkinson: Differential role of D-1 and D-2 receptors

The non competitive antagonist of N-methyl-D-aspartate (NMDA) receptors MK-801, at doses which did not produce any behavioural modification per se, increased by about 40% the contralateral turning induced by the dopaminergic (DA) D-1/D-2 agonist L-dopa in rats bearing a unilateral lesion of the DA nigro striatal neurons. Administration of MK-801 in combination with selective agonists of the D-1 (SKF 38393) or D-2 (LY 171555) receptor, induced an increase of about 280% of D-1 mediated turning and a 70% decrease of D-2 mediated turning. Analysis of the potentiation of L-dopa mediated turning by MK-801 after selective D-1 receptor blockade by SCH 23390, revealed that the increase of turning was related to the stimulation of D-1 receptors by L-dopa. Immunocytochemical visualization of the proto-oncogene c-fos in the caudate-putamen (CPu) of lesioned rats, revealed a sparse c-fos positive nuclei in the lesioned CPu of rats treated with SKF 38393 alone, while after combined administration of MK-801 and SKF 38393 dense labelling of nuclei was found. The results indicate that blockade of NMDA receptors by MK-801 acts synergistically with D-1 agonists in the induction of turning after DA denervation and shows that these changes are correlated with c-fos induction in specific areas of the CPu.

Functions of dopamine in the extrapyramidal and limbic systems. Clues for the mechanism of drug actions

Dopamine (DA) is a neurotransmitter which modulates the transfer of information along fast-conducting pathways at the level of two main nodal points: the ventral striatum, composed by limbic areas (nucleus accumbens, tuberculum olfactorium) and the dorsal striatum, composed by extrapyramidal nuclei (caudate-putamen). These two subdivisions of the enlarged basal ganglia, are provided with different functions; accordingly, limbic DA plays an active role in goal-oriented (motivated) behaviour; instead, extrapyramidal DA is essential for execution of learned motor programs and its impairment results in the symptoms of Parkinson's disease. Various centrally acting drugs are able to interfere with DA transmission or with other neurotransmitter systems which interact with DA. Drugs of abuse owe their incentive properties to a preferential stimulation of DA transmission at the level of the limbic dopaminergic areas. On the other hand, drugs able to block glutamatergic transmission on NMDA receptors are able to selectively potentiate the action of DA at the level of a specific type of DA-receptors, the D-1 type. Knowledge of the role of DA in the brain can provide the basis not only for understanding the mechanism of drug action but also for developing new strategies for the treatment of drug abuse and extrapyramidal disorders.

Opposite effects of NMDA receptor blockade on dopaminergic D1- and D2-mediated behavior in the 6-hydroxydopamine model of turning: relationship with c-fos expression

In rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopaminergic pathway, I-dihydroxyphenylalanine (L-DOPA) induces contralateral turning through activation of denervated D1 and D2 receptors. Blockade of N-methyl-D-aspartate (NMDA) receptors by the noncompetitive antagonist (+)MK-801 (0.1 mg/kg, i.p.), potentiated L-DOPA-induced contralateral turning. In 6-OHDA lesioned rats, selective agonists of D1 (SKF 38393, CY 208-243) or D2 (LY 171555) receptors also induce contralateral turning; however, (+)MK-801 pretreatment, although markedly potentiating D1, almost completely inhibited D2-mediated turning. The potentiation of SKF 38393-induced contralateral turning by MK-801 was stereospecific and was observed also with the noncompetitive NMDA antagonist phencyclidine, and with the competitive antagonist CPP. Administration of the D1 antagonist SCH 23390 (0.1 mg/kg s.c.) blocked (+)MK-801-induced potentiation of L-DOPA contralateral turning, confirming the D1 nature of the effects observed. Expression of the early gene c-fos in the caudate-putamen (CPu) is known to be activated by stimulation of supersensitive D1 receptors. Immunohistochemical studies on c-fos revealed sparse c-fos positive nuclei in the lesioned CPu after 1.5 mg/kg of SKF 38393, whereas after combined administration of (+)MK-801 and SKF 38393, dense labeling of nuclei was obtained in the dorso-lateral aspect of the CPu. Therefore, blockade of NMDA receptors acts synergistically with D1 and antagonistically with D2 receptor stimulation in the 6-OHDA model of turning, suggesting that different neuronal pathways are involved in the mediation of D1 and D2 responses.

Reliability of individual differences for H-reflex recordings

Complementary data from two closely-related experiments were analyzed to investigate the reliability of individual differences of H-reflex amplitude. Some concomitant analysis of M-reflex was also included. The purpose was to do this in a manner that was more direct and more detailed than found hitherto in the literature. Fundamental techniques espoused particularly by F.M. Henry (1969) formed the basis of this approach. The aims included a clearer quantification of reliability with a distinction between inter- and intra-individual sources of variation, an analysis of the effects different numbers of trials had on reliability, and an investigation of the progression of reliability over a 20-trial sequence of observations. The control conditions of both experiments were designed to be essentially identical with respect to subject position, stimulus and recording configurations. Experiment 1 had 20 subjects, four control conditions of 10-trials in each while experiment 2 had 18 subjects, five control conditions and 20 trials. The posterior tibial nerve was percutaneously stimulated every 10 sec. and surface electromyographic recordings were made from the soleus muscle. H-reflex and M-reflex amplitudes were measured on every trial. It was found that the reliability of individual differences of both H-reflex and M-reflex was extremely robust with the majority of coefficients being above .950. In addition, the reliabilities remained high when as few as four trials were examined. The pattern of individual differences over the longer series of trials confirmed the stability of interindividual differences and showed that subjects became more consistent in their responses as trials progressed.(ABSTRACT TRUNCATED AT 250 WORDS)

H-reflex modulation during manual muscle massage of human triceps surae

An investigation of the effect of a six-minute manual muscle massage on the excitability of the spinal reflex pathway in 20 able-bodied subjects was undertaken. H-reflex recordings were obtained from the right soleus muscle, which was the site being massaged. Skin temperature and antagonist activity were monitored in an attempt to explain the changes observed in a previous study. The experimental paradigm chosen was an A-B-A interrupted-time series design consisting of two pretreatment, two treatment (massage), and two posttreatment conditions. H-reflex amplitudes recorded during both massage conditions (.76 +/- .58 mV, .76 +/- .61 mV) were significantly reduced (F5,90 = 69.04, p less than .01) in comparison to all other (before and after) conditions (2.58 +/- .75 mV, 2.56 +/- .71 mV, 2.82 +/- 1.14 mV, and 2.89 +/- .82 mV, respectively). This decrease could not be explained conclusively by changes in skin temperature, nerve conduction velocity, or antagonist recruitment, thus indicating a decrease in spinal reflex excitability attributed to massage. These findings also support our earlier report, which stated that H-reflex amplitudes are reduced only during the period of tissue manipulation, regardless of the duration of the massage.

Surgical treatment of cardiac arrhythmias

This report describes 20 consecutive patients who underwent surgical procedures for treatment of cardiac arrhythmias. 16 patients have been operated for WPW syndrome, always using the epicardial approach, without extracorporeal circulation. Three patients underwent surgery for atrio-ventricular nodal reentrant tachycardia, using a discrete perinodal cryotreatment, during normothermic extracorporeal circulation. In one case we used cryoablation of the atrial myocardium below the coronary sinus to treat atrial flutter. This operation was performed under normothermic extracorporeal circulation. In our observations, there was no early or late death; postoperative complications developed in 1 patient (5%) due to pericarditis. Ablation of the AP was completely successful in all the cases (100%) operated for WPW as well as for AVNRT syndromes and atrial flutter.

Effects of massage on alpha motoneuron excitability

The purpose of this study was to investigate the specificity of the effects of massage (petrissage) on spinal motoneuron excitability as measured by changes in the peak-to-peak amplitude of H-reflex recordings. H-reflexes (and M-responses) were recorded from the distal aspects of the right triceps surae muscle of 8 men and 8 women, aged 20 to 37 years, with no neuromuscular impairments of the lower extremities. The H-reflexes were recorded during five control and four experimental conditions (20 trials at each condition). The control conditions (C1-C5) preceded and followed each experimental condition, providing a measure of the stability of the H-reflex. Each experimental condition consisted of a 4-minute period of massage of the ipsilateral and contralateral triceps surae and hamstring muscle groups (ITS, CTS, IHS, and CHS, respectively). The mean peak-to-peak amplitude of the H-reflex was found to be stable (range = 1.91-1.95 mV) across the five control conditions. H-reflex amplitudes recorded during the experimental conditions indicate that massage of the ITS resulted in a reduction of the H-reflex (0.83 mV) in comparison with the pretest control condition (C1) and the remaining experimental conditions (range = 1.77-2.23 mV). This difference was significant, and subsequent Newman-Keuls tests indicated a specificity of the effects of massage on the muscle group being massaged. [Sullivan SJ, Williams LRT, Seaborne DE, Morelli M. Effects of massage on alpha motoneuron excitability.

Positive and negative interactions in the behavioural expression of D1 and D2 receptor stimulation in a model of Parkinsonism: role of priming

Previous exposure to a dopaminergic agonist (priming) strongly potentiates contralateral turning behaviour in response to D1 and D2 agonists in unilaterally 6-hydroxydopamine-lesioned rats. In order to study the influence of priming on the behavioural interaction of D1 and D2 receptors, we examined the effect of selective D1 and D2 receptor blockade on the contralateral turning induced by the mixed D2/D2 agonist apomorphine in drug-naive and primed 6-hydroxydopamine-lesioned rats. In drug-naive rats, apomorphine induced a dose-related, apparently monophasic rotation curve. Administration of selective D1 (SCH 23390) or D2 (raclopride) antagonists abolished the contralateral turning induced by 0.1 mg/kg of apomorphine and partially inhibited that induced by 0.5 mg/kg. In primed rats low doses of apomorphine (0.05 mg/kg) induced an apparently monophasic contralateral turning which was reduced by D1 receptor blockade and completely abolished by D2 receptor blockade; a higher dose of apomorphine (0.1 mg/kg) instead elicited a biphasic (two-peak) pattern of rotation. After this dose of the agonist, blockade of D1 or D2 receptors abolished the second peak of rotation but, while D1 blockade reduced the total number of turns, D2 blockade failed to do so. Quantitative analysis of the interaction between D1 and D2 receptors in the overall turning effect, as well as in the time-course of turning behaviour, indicates that D1 and D2 receptors interact not only positively but also negatively. After higher doses of apomorphine, both negative and positive interactions take place sequentially during the time-course of apomorphine action and provide a clue for explaining the two-peak pattern of rotation observed after apomorphine in rats previously exposed to the drug.

Changes in the D1 receptor-adenylate cyclase complex after priming

The D1 agonist, SKF 38393, failed to induce contralateral turning in drug-naive rats lesioned unilaterally with 6-hydroxydopamine from 17 days. Priming with a dopamine agonist, such as the D2 agonist, LY 171555, three days before, made SKF 38393 fully effective in inducing contralateral turning. Analysis of D1 receptor binding in striata of drug-naive and primed rats showed no change in the Bmax and Kd. In contrast, dopamine-stimulated adenylate cyclase showed a decrease in its Km for dopamine in the lesioned side of primed rats as compared with drug-naive rats. Thus, priming appears to elicit changes at the level of the transduction mechanism of D1 receptors rather than in the D1 recognition site itself.

Comparison of human triceps surae H-reflexes obtained from mid and distal recording sites

The purpose of this study was to determine whether a distal triceps surae recording site produced H-reflex responses similar to those obtained from the conventional soleus location in 10 healthy subjects at rest. H-reflex and M-response recruitment profiles were generated and the peak-to-peak amplitudes were measured from the two sites simultaneously. Following this, an H-reflex control signal was determined (peak-to-peak amplitude approximately equal to 30% Mmax) and 4 series of 10 trials were recorded at 5 minute intervals. A paired t-test showed non-significant (p greater than 0.05) differences in Hmax, Mmax, and Hmax: Mmax values recorded from the two sites. Linear regression analyses of recruitment profile H-reflexes and M-responses, obtained simultaneously from the two recording sites showed strong correlations (r greater than 0.90, p less than 0.001). To assess the stability of the reflex over time, intraclass correlation coefficients (ICC) were computed for each recording site (R = 0.99 in both instances). Thus the distal recording site, just proximal to the flare of the medial malleolus, is an acceptable alternative to the conventional recording location. This permits recording H-reflex amplitude changes, resulting from the application of a therapeutic intervention to the calf muscles, without having to remove and reposition the recording electrodes.

Disodium cromoglycate versus diet in the treatment and prevention of nickel-positive pompholyx

In some cases that have been diagnosed as contact allergy to nickel, there are repeated cutaneous eruptions of pompholyx, even in areas with no direct contact with the metal. The possible alimentary origin of dyshidrotic eczema should be considered when deciding on therapy. We have collected the clinical data for 24 patients with dyshidrotic eczema caused by nickel, to evaluate the benefit of a low-nickel diet versus treatment with oral disodium cromoglycate, comparing both objective and subjective symptoms. A low-nickel diet does not improve these patients but those treated with DSCG reacted better, from both objective and subjective point of view, than either the controls or the patients treated by diet. We next did intestinal permeability tests before therapy and after 15 days of treatment. We found that nickel uptake diminishes simultaneously with the reduction of absorption through the smaller aqueous "pores". This phenomenon was greatest after DSCG. We suggest that DSCG can help selected cases of pompholyx.

Stereospecific blockade of N-methyl-D-aspartate transmission by MK 801 prevents priming of SKF 38393-induced turning

In rats unilaterally lesioned with 6-hydroxydopamine, the D-1 agonist SKF 38393 (3 mg/kg SC) induced contralateral turning only after priming with a dopaminergic agonist such as apomorphine. Administration of the N-methyl-D-aspartate receptor antagonist (+) MK 801 (0.1 mg/kg IP) 15 min before apomorphine (0.1 mg/kg SC) prevented the ability of apomorphine to act as a primer while potentiating its acute contralateral turning effects. The inactive isomer (-) MK 801 was without effect. The results indicate that the N-methyl-D-aspartate receptor exerts a permissive role on priming.

Quantitative autoradiographical analysis of the age-related modulation of central dopamine D1 and D2 receptors

Quantitative autoradiography of [3H]SCH 23390 and [3H](-)-sulpiride binding was performed in the brain of rats of various ages (3, 11 and 24 months) in order to study the changes in D1 and D2 receptor density with age. Binding of [3H]SCH 23390 in the caudate-putamen decreased progressively and markedly at rostral levels in 11- and 24- compared with 3-month-old rats (max. decrease -63%) while at caudal levels significant decrease was observed only in 24-month-old rats. [3H](-)-Sulpiride binding progressively decreased during aging in the caudate-putamen at rostral levels and the decrease was more pronounced laterally (-70% at 24 months), while at caudal levels no significant decrease was observed. D1 and D2 binding sites also decreased in the nucleus accumbens and olfactory tubercle of aged rats, while in the substantia nigra only the D1 receptors appeared to be modified with aging. No change was found in the entopeduncular nucleus, amygdala, frontoparietal, suprarinal-prefrontal and anterior cingulate cortex. The results indicate that the age-associated decrease of D1 and D2 receptors is not widespread, being confined to dopaminergic areas with high density of dopamine receptors.

Substantia nigra as a site of origin of dopamine-dependent motor syndromes induced by stimulation of mu and delta opioid receptors

Opioid agonists having different affinity for delta and mu receptors were injected bilaterally in the substantia nigra (SN) of rats. The selective agonist of mu receptors N-MePhe3,-D-Pro4 morphiceptin (PLO 17) produced a stereotyped behavior characterized by stereotyped sniffing and gnawing antagonized by the irreversible antagonist of mu receptors beta-funaltrexamine. In contrast, bilateral intranigral injection of the selective delta agonist D-Pen2,D-Pen5 enkephalin (DPDPE) elicited dose-dependent exploratory behavior and rearing but failed to produce gnawing. The behavioral syndrome induced by DPDPE was significantly reduced by the selective delta antagonist ICI 174,864. Naloxine, a non-selective opioid antagonist, antagonized the effects of both compounds. SCH 23390 and haloperidol, two antagonists of dopaminergic D1 and D2 receptors, respectively, blocked the effects of PLO 17 and DPDPE. The results indicate that stimulation of specific opioid receptor types in the SN elicits specific behavioral syndromes and suggest that the SN might be the site of origin of certain items of the behavioral syndrome evoked by systemic opiates. These items might be mediated by activation of dopaminergic neurons of the ventral mesencephalon.

Electrophysiological evidence for interhemispheric transmission of visual information in man

1. Electrophysiological evidence is presented of interactions between two stimuli (sinusoidal gratings of equal spatial frequency but different contrast, phase-reversed sinusoidally at different temporal frequencies) located on opposite side of, and within a few degrees from, the vertical meridian. 2. These interactions are revealed by a depression of the cortical visual evoked potential (VEP) evoked by the grating of lower contrast in the presence of the grating of higher contrast. They are similar to, albeit weaker than, those obtained with superimposed asynchronously modulated gratings. 3. The VEP reduction occurs also if the stimuli are presented dichoptically. 4. It does not occur if the gratings are located one above the other either on the same or on opposite sides of the vertical meridian. 5. The strength of the VEP reduction depends on the relative contrast of the two gratings and vanishes for spatial frequencies beyond 4 cycles/deg and temporal frequencies of the high-contrast grating beyond 10 Hz. 6. The results are in agreement with data on visual callosal connections in animals and confirm previous psychophysical findings (Berardi & Fiorentini, 1987) indicating the particular properties of the interhemispheric cross-talk between symmetric regions of the visual field astride the vertical meridian in man.

Time and dose dependence of the 'priming' of the expression of dopamine receptor supersensitivity

The D-1 receptor agonist, SKF 38393 (2 mg/kg s.c.), failed to elicit contralateral turning when administered to drug-naive rats 17 days after unilateral 6-hydroxydopamine (6-OHDA) lesioning of the medial forebrain bundle, while it elicited intense contralateral turning 90 days post-lesioning. On the other hand the D-1/D-2 receptor agonist, apomorphine (0.1 mg/kg s.c.), induced contralateral turning in drug-naive rats lesioned 14 days earlier and made the administration of SKF 38393 (2 mg/kg s.c.) 3 days later effective to evoke contralateral turning ('priming'). The effectiveness of apomorphine as a primer of SKF 38393-induced turning depended critically on the interval between the administration of the two agonists. Effectiveness was minimal after 3 h and increased after 6-12 h, peaked at 72 h and was reduced after 10 days. The D-2 receptor agonist, LY 171555 (0.2 mg/kg s.c.), was also effective as a primer of SKF 38393-induced contralateral turning and this effect also was dependent upon the interval between priming and SKF 38393 administration. Moreover, priming was dependent on the dose of drug used as primer and on the dose of SKF 38393 used as a challenge. In contrast to SKF 38393, priming was unable to make effective a dose of LY 171555 that was ineffective in drug-naive rats, suggesting that LY 171555 affects D-1-dependent turning to a greater extent than D-2-dependent turning. The results indicate that the priming phenomenon is rather strictly time- and dose-dependent.

Surgical correction of congenital left coronary-pulmonary artery fistula and rheumatic mitral valve disease. Case report

A 56-year-old woman with stenosis and incompetence of the mitral valve and clinical signs of congestive heart failure was found to have a communication between the left anterior descending coronary artery and the pulmonary trunk. A mitral valve prosthesis was inserted and the fistula was closed from within the pulmonary artery.

Agonist-induced homologous and heterologous sensitization to D-1- and D-2-dependent contraversive turning

A low dose of the D-1 receptor agonist SKF 38393 (2.0 mg/kg s.c.) 14 days post-lesion failed to induce contraversive turning in male Sprague-Dawley rats lesioned unilaterally in the medial forebrain bundle with 6-hydroxydopamine (6OHDA). Priming with a single administration of the specific D-2 agonist LY 171555 (0.2 mg/kg s.c. 3 days before), which itself elicited contraversive turning, made SKF 38393 (2.0 mg/kg s.c.) very active to produce contraversive turning. Priming with LY 171555 (0.2 mg/kg s.c. 3 days before) potentiated the contraversive turning in response to a low dose of LY 171555 (0.05 mg/kg s.c.). In naive 6OHDA-lesioned rats a rather high dose of SKF 38393 (10 mg/kg s.c.) was needed to induce a low intensity contraversive turning. Priming with a single administration of SKF 38393 (10 mg/kg s.c. 3 days before) made an otherwise ineffective dose of SKF 38393 (2.0 mg/kg s.c.) very effective to produce contraversive turning. The results indicate that the sensitization to the behavioural expression of supersensitivity for a given DA-receptor type follows not only priming with agonists for the same DA-receptor type (homologous sensitization) but also priming with agonists for a different DA-receptor type (heterologous sensitization).

6-Hydroxydopamine lesions reduce specific [3H]sulpiride binding in the rat substantia nigra: direct evidence for the existence of nigral D-2 autoreceptors

[3H]Sulpiride bound to substantia nigra homogenates in a saturable manner and with a pharmacological profile typical of a specific D-2 ligand. Unilateral 6-OH-dopamine (DA) lesions of the nigrostriatal DA neurons reduced by 27-46% the Bmax of the specific [3H]sulpiride binding in substantia nigra homogenates depending on the time after 6-OHDA lesion and significantly increased the Bmax in the caudate. KDs remained unchanged in both areas. The localization of specific [3H]sulpiride binding and its reduction in the substantia nigra of the 6-OHDA-lesioned side were confirmed by quantitative autoradiography. The results provide evidence for the existence of D-2 autoreceptors in substantia nigra.