Neuroprotective effects of a selective N-methyl-D-aspartate NR2B receptor antagonist in the 6-hydroxydopamine rat model of Parkinson's disease.

1. Current pharmacotherapies for the treatment of Parkinson's disease (PD) are largely symptomatic and do not attenuate the characteristic nigral (dopamine) cell loss. 2. Using the 6-hydroxydopamine (6-OHDA) rat model of PD, we investigated the novel, potentially neuroprotective compound BZAD-01, which is an N-methyl-D-aspartate (NMDA) glutamate receptor antagonist selective for the NR2B subunit. 3. Forty female Sprague-Dawley rats were pretreated with either 10 mg/kg BZAD-01 or vehicle (5% sucrose and 0.1% ascorbate) in their drinking water for 11 days prior to and for 3 days following 6-OHDA surgery. During surgery, rats received an injection of either a toxic dose of 16 microg 6-OHDA or a non-toxic dose of 1 microg 6-OHDA (sham) into the medial forebrain bundle. A series of behavioural tests, including curling (measuring body axis bias), head position bias and narrow beam, was performed fortnightly for 8 weeks after surgery to assess the effects of BZAD-01 pretreatment on parkinsonism. Drug-induced rotational asymmetry was also assessed just before rats were killed. Post-mortem immunohistochemistry was performed to quantify the degree of nigral dopamine cell loss. 4. Pretreatment of 6-OHDA-lesioned rats with BZAD-01 significantly reduced the amount of dopamine cell loss and significantly improved all behavioural measures. Furthermore, there was no significant difference in any of the behavioural measures between lesioned rats pretreated with BZAD-01 and rats that underwent sham surgery.

Developing a preclinical model of Parkinson's disease: a study of behaviour in rats with graded 6-OHDA lesions.

Injection of increasing concentrations of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle (MFB) can be used to establish a graded model of different clinical stages of Parkinson's disease (PD). We investigated the relationship between behavioural alterations and loss of dopaminergic neurons in the substantia nigra pars compacta (SNc). Forty female Sprague-Dawley rats were injected with either (i) 4 microg (ii) 8 microg or (iii) 16 microg 6-hydroxydopamine (6-OHDA) to mimic the preclinical, mild and advanced clinical stages of PD, respectively. Vehicle was injected in a separate control group. Behaviours analysed included postural asymmetry, balance, locomotion, sensorimotor deficits and apomorphine rotation. At post-mortem the degree of tyrosine immunoreactive dopaminergic cell (TH-ir) loss was then estimated. There was a graded and consistent trend in each of the behaviours studied with respect to cell loss between the different sized lesion groups when examined using correlation analysis (all comparisons, r > 0.8, p < 0.001). Rats with large lesions demonstrated more significant behavioural changes over 8 weeks of testing than those with intermediate and smaller lesions (group comparisons p < 0.001). PD symptomatology became overt when cell loss reached 70%, however some significant changes can be observed with as little as 40% dopaminergic cell loss. Thus, injection with increasing concentrations 6-OHDA into the MFB can produce increasing extents of cell loss and behavioural changes, which were well correlated. This graded model can be useful for testing potential neuroprotective compounds for PD.

Behavioural effects of parafascicular thalamic lesions in an animal model of parkinsonism.

We recently reported that the centromedian-parafascicular thalamic complex (CM-Pf) degenerates in Parkinson's disease and progressive supranuclear palsy. The contribution of such thalamic pathology to disease symptoms has not yet been established. The present study therefore investigated the behavioural impact of lesioning the corresponding thalamic region (termed Pf) on a range of behaviours present in rodents. There were four surgical groups: (1) sham medial forebrain bundle (mfb)+sham Pf, (2) 6-OHDA mfb lesion+sham Pf, (3) sham mfb+NMDA Pf lesion, (4) 6-OHDA+NMDA Pf lesions. Posture, sensory functions and apomorphine-induced rotational asymmetry were assessed before and after each surgery. Other assessments performed including a timed motivational task, grooming behaviours and piloerection. 6-OHDA lesions induced postural (ipsilateral curling and head position biases), sensorimotor (increased latency to respond to tactile stimulation of the contralateral side when eating or grooming) and rotational abnormalities (contralateral circling after apomorphine). The main effects of combined 6-OHDA+Pf lesions were improved performance in a motivational task (decreased latency to retrieve reward) but worsened piloerection, relative to animals with either 6-OHDA or Pf lesions alone. The thalamic zone common to all lesioned animals involved the posterior Pf. Our data suggests that the posterior CM-Pf may be involved in motivational responses and autonomic dysfunction in parkinsonian disorders.

Perceptions of urinary symptoms and health-care-seeking behaviour amongst men aged 40-79 years.

BACKGROUND: Little is known about why men fail to seek medical help for urological symptoms. AIM: This study was designed to document men's perceptions of urinary symptoms and to increase understanding of health-care-seeking behaviour. METHOD: A stratified random sample of men aged 40-79 years was drawn from the age-sex register of a health centre in Central Scotland. Two hundred men were interviewed using semi-structured qualitative techniques and asked to complete a symptom questionnaire. The response rate was 65%. RESULTS: Urinary symptoms reported to be most bothersome were dribbling, hesitancy and straining. All but the youngest age group (40-49 years) associated developing urinary symptoms with ageing. This was considered to be a reason not to consult a doctor. Most symptoms were not thought to be serious. Pain, haematuria and acute retention gave cause for concern, and were perceived as reasons for seeking medical help. Although urinary symptoms interfered with selected activities in daily life, this was not a worry to the men and was not seen to be a sufficient reason alone to consult their general practitioner. CONCLUSION: The insidious development of urinary problems over time reinforces the belief that it is part of getting older and accounts for the accommodation of symptoms within men's everyday living experiences. Bothersomeness associated with urinary symptoms was not synonymous with worry or problems. Doctors must be prepared to initiate discussion about urinary function in order to assess the impact of symptoms on an individual's daily life.

Ethnography and the ethics of undertaking research in different mental healthcare settings.

This paper draws on our experiences of seeking research ethics and management approval for a 1-year ethnographic research study in three mental health settings. We argue that the increased bureaucratization of research governance in the UK is paternalistic and unfit for qualitative, non-interventionist study designs. The classification of all mental health services users as 'vulnerable' is also disempowering and contrary to government calls to increase user involvement in research processes. We relate our difficulties in accessing National Health Service sites to undertake our study despite endorsement by senior managers. The current research ethics system reinforces the gatekeeping role of front-line National Health Service staff but this may work to bias samples in favour of 'amenable' service users and exclude others from having their views and experiences represented in studies over the long-term.

Subtle cardiovascular dysfunction in the unilateral 6-hydroxydopamine-lesioned rat.

The present study evaluated whether the unilateral 6-hydroxydopamine (6-OHDA) model of Parkinson's disease produces autonomic deficits. Autonomic parameters were assessed by implanting a small radiofrequency telemetry device which measured heart rate variability (HRV), diurnal rhythms of heart rate (HR), core body temperature (cBT) and locomotor activity (LA). Rats then received 6-OHDA lesion or sham surgery. 6-OHDA lesioned rats exhibited head and body axis biases, defective sensorimotor function ("disengage" test), and prominent apomorphine rotation (all P < .05 versus controls). Diurnal rhythm of HR was lower for 6-OHDA lesioned rats (n = 8) versus controls (n = 6; P < .05). Whilst HR decreased similarly in both groups during the day, there was a greater decrease in HR for the 6-OHDA lesioned rats at night (by 38 b.p.m. relative to 17 b.p.m. for controls). LA and cBT did not differ between surgery groups. This study indicates the unilateral 6-OHDA model of PD shows subtle signs of cardiovascular autonomic dysfunction.

Behavioural effects of a selective NMDA NR1A/2B receptor antagonist in rats with unilateral 6-OHDA+parafascicular lesions.

Experimental lesions involving the parafascicular (Pf) nucleus and medial forebrain bundle (MFB) may model to some extent the pathological loss of glutamatergic neurons from the centromedian-parafascicular (CM-Pf) complex and nigral dopaminergic cell loss observed clinically at post-mortem in Parkinson's disease (PD) cases. Our study investigated whether there were alterations in symptomatology in such rats with unilateral 6-OHDA+Pf lesions after treatment with either a selective NR1A/NR2B NMDA antagonist and/or l-dopa. Rats were given dual surgery to the MFB with 6-hydroxydopamine (6-OHDA) and Pf with N-methyl-d-aspartate (NMDA). (i) An NR1A/NR2B selective NMDA antagonist (BZAD-01; 10mg/kg), (ii) l-dopa (25mg/kg), (iii) BZAD-01+l-dopa (10mg/kg; 25mg/kg) or (iv) vehicle solution were administered for 6 weeks, during which behavioural testing was performed. BZAD-01 improved postural asymmetry in the first month as well as apomorphine-induced rotation. The latter was also improved by l-dopa in this model. These data support the use of selective NR1/NR2B NMDA antagonists in the therapeutics of PD.

Evaluation of behavioural effects of a selective NMDA NR1A/2B receptor antagonist in the unilateral 6-OHDA lesion rat model.

The degeneration of the dopaminergic nigrostriatal pathway in Parkinson's disease (PD) is associated with altered transmission at striatal NMDA receptors containing NR2B subunits. We investigated a potential novel therapeutic compound, 4-trifluoromethoxy-N-(2-trifluoromethyl-benzyl)-benzamidine (BZAD-01), a selective NMDA NR1A/2B receptor antagonist for PD and compared it with levodopa, the standard treatment for PD. This study also evaluated whether combining levodopa and BZAD-01 gave better improvements of parkinsonian symptoms. Parkinsonism was induced by microinjection of the toxin, 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle (MFB) of 40 Sprague-Dawley rats. Parkinsonism and the efficacy of drugs were assessed using a battery of behavioural tests including balance beam, apomorphine-induced rotation, body axis bias or "curling", head position bias and disengage sensorimotor latency test. Immunohistochemistry was performed on post-mortem tissue to estimate the loss of dopaminergic neurons. The main effects were that BZAD-01 co-administration prevented chronic levodopa-induced potentiation of apomorphine rotation. However levodopa-treated rats were slower than either controls or BZAD-01-treated rats in the locomotor test. The improvement in the apomorphine rotation test suggests that BZAD-01 may be a useful adjunct to levodopa monotherapy.