Neurite outgrowth through lesions of neonatal opossum spinal cord in culture.

The aim of these experiments was to analyze neurite outgrowth during regeneration of opossum spinal cord isolated from Monodelfis domestica and maintained in culture for 3-5 days. Lesions were made by crushing with forceps. In isolated spinal cords of animals aged 3 days, neurites entered the crush and grew along the basal lamina of the pia mater.

cDNA libraries from identified neurons.

One approach to studying the changes in gene expression which underlie differentiation is to construct cDNA libraries from different tissues or at different stages of development. However, generating representative cDNA libraries from heterogeneous tissues such as the nervous system is often a real problem. Here, we describe a reproducible method for the construction of large and complex cDNA libraries from a few leech Retzius or P neurons (equivalent to about 50 pg of mRNA) using polymerase chain reaction-based technology.

Advantages of using microfabricated extracellular electrodes for in vitro neuronal recording.

We describe fabrication methods and the characterisation and use of extracellular microelectrode arrays for the detection of action potentials from neurons in culture. The 100 microns2 platinised gold microelectrodes in the 64 electrode array detect the external current which flows during an action potential with S:N ratios of up to 500:1, giving a maximum recorded signal of several millivolts. The performance of these electrodes is enhanced if good sealing of the cells over the electrodes is obtained and further enhanced if the electrodes and the cells lie in a deep groove in the substratum.

Simultaneous multisite recordings and stimulation of single isolated leech neurons using planar extracellular electrode arrays.

Planar extracellular electrode arrays provide a non-toxic, non-invasive method of making long-term, multisite recordings with moderately high spatial frequency (recording sites per unit area). This paper reports advances in the use of this approach to record from and stimulate single identified leech neurons in vitro. A modified enzyme treatment allowed identified neurons to be extracted with very long processes.

Differential responses to a single antidepressant in recurrent episodes of major depression.

Objectives: The study examined whether patients who responded to an antidepressant in one episode of depression responded to the same agent in a subsequent episode. It also sought to determine whether in a subsequent episode clinicians prescribed an antidepressant that had previously been effective.

Methods: Charts of inpatients with a diagnosis of major depression who were consecutively admitted to general hospital psychiatric wards were screened to determine whether the patients met the inclusion criteria of recurrent major depression and had responded to antidepressant therapy in a previous episode.

Expression and localization of amiloride-sensitive sodium channel indicate a role for non-taste cells in taste perception.

Salty taste is blocked by the diuretic amiloride, which inhibits specific sodium channels. We have isolated an amiloride-sensitive sodium channel (ASSC) from taste tissues by polymerase chain reaction and screening of a cDNA library prepared from rat circumvallate papillae. Northern analysis reveals ASSC in taste and non-taste tissues with the highest level of expression of ASSC in the lung.

cDNA libraries from a few neural cells.

One of the most powerful approaches to the molecular analysis of differential gene expression is to construct cDNA libraries corresponding to different tissues or developmental stages, and then to enrich for genes expressed in a particular tissue or at a particular time by subtractive hybridisation. Our aim is to reduce the complexity of neuronal cDNA libraries by generating libraries from the mRNA of a single cell. The system chosen is the Retzius cell of the leech, a large neurone which can be unambiguously dissected out.

Cellular and molecular approaches to neural repair in the medicinal leech.

Investigation of repair processes and the effects of damage in the leech has the advantage that it is possible to work with single neurons, and that leech neurons can regenerate. The effects of surface topology on neuronal outgrowth in culture were investigated using patterned substrates produced by photolithography. On grooved substrates with a depth, width and separation of 2 microns, the processes of cultured neurons showed significant alignment.

Verbal learning by major depressive disorder patients during treatment with fluoxetine or amitriptyline.

After 1 week of a single-blind placebo period, and prior to being randomly assigned to receive treatment with either fluoxetine or amitriptyline, patients meeting strict criteria for a diagnosis of major depressive disorder were given an auditory verbal learning test of working memory, and a blood sample was drawn. After 3 weeks of drug treatment with either amitriptyline or fluoxetine, the patients' symptoms were evaluated, the verbal learning test was repeated, and a second blood sample was taken. The clinical evaluation, the verbal learning test and the blood drawing were repeated a third time 3 weeks after the second assessment.

Stretch receptors and body wall muscle in leeches.

1. A new kind of muscle receptor has been described in the medicinal leech, the first stretch receptor in a soft-bodied invertebrate to be identified and characterized. 2.

Longitudinal effect of amitriptyline and fluoxetine treatment on plasma phenylacetic acid concentrations in depression.

Unconjugated (U-PAA), conjugated (C-PAA), and total phenylacetic acid (T-PAA) concentrations in blood plasma and monoamine oxidase (MAO) activity in platelets towards phenylethylamine (PE) were determined in 40 drug-free, depressed patients (23 melancholic, 17 nonmelancholic) from five psychiatric treatment centers, and in 34 normal healthy volunteers. No significant differences were found between controls and all depressed patients or between melancholic and nonmelancholic depressed patients. Treatment of the depressed patients with amitriptyline or fluoxetine over a 6-week period resulted in clinical improvement and in a significant increase in plasma PAA concentrations.

A comparison of fluoxetine and amitriptyline in the treatment of major depression.

Fluoxetine, a new serotonin uptake blocking antidepressant, was compared with amitriptyline in a double-blind study. Patients were diagnosed as having major depression, according to DSM-III criteria, when interviewed with the Diagnostic Interview Schedule. There was significant improvement in patient and observer ratings of depression in both groups, with no difference between groups.

Deuterium-labelled p-tyramine challenge test and phenolsulfotransferase activity in depressed patients--failure to replicate decreased p-tyramine conjugation in depression.

1. Depressed and normal subjects were challenged with deuterium-labelled p-tyramine and urine was collected for 3 h. 2.

New growth elicited in adult leech mechanosensory neurones by peripheral axon damage.

1. New growth in cutaneous mechanosensory neurones elicited by axotomy or axon crush was studied using intracellular injection of horseradish peroxidase at different times after the lesion, ranging from a few days to over a year. 2.

Hyperpolarizing responses to stretch in sensory neurones innervating leech body wall muscle.

1. The membrane properties, morphology and physiological responses of peripherally located sensory neurones that innervate body wall muscle of the leech Hirudo medicinalis have been investigated using intracellular recording and dye injection techniques. 2.

A case of atypical psychosis associated with alexithymia and a left fronto-temporal lesion: possible correlations.

The case history is presented of a man with an atypical psychosis and classical clinical features of alexithymia. On his last admission, the patient presented with starvation and hypernatremic coma. A CT scan, which was done because of the coma, revealed a large left fronto-temporal arachnoid cyst.

Expanded receptive fields of cutaneous mechanoreceptor cells after single neurone deletion in leech central nervous system.

1. Individual sensory neurones responding to touch (T) and to noxious (N) stimuli applied to the skin of the leech were killed by injecting pronase into their cell bodies, situated within the C.N.

Physiological responses, receptive fields and terminal arborizations of nociceptive cells in the leech.

The physiological responses, receptive fields and morphology of individual nociceptor (N) neurones have been studied in the leech. In each of the midbody ganglia there are four N cells (two on either side). Each N cell has a distinctive territory that it supplies in the periphery, on the surface or internally.