N. Milici

Ventricle-to-brain ratio in schizophrenia: a controlled follow-up study

The presence of enlarged lateral cerebral ventricles on computed tomography (CT) scans of a subset of schizophrenic patients has been reported by several authors (for a review, see Shelton and Weinberger 1986). This enlargement is commonly believed to predate the onset of illness and to be nonprogressive: in fact, most studies found no correlation between lateral ventricle size and duration of illness, and ventricular enlargement was also observed in young patients with schizophreniform disorder (Weinberger et al. 1982). Nevertheless, controversy on this topic persists. It has been argued (Woods and Wolf 1983) that the relationship between ventricle size and duration of illness was missed in some investigations as a consequence of the homogeneity of the patient sample with respect to the duration itself. Indeed, some studies ex-

Clinical and neuropsychological correlates of cerebral ventricular enlargement in schizophrenia

A comprehensive assessment of computed tomography (CT) with respect to clinical, historical and neuropsychological variables has been carried out in a sample of DSM III schizophrenics fairly heterogeneous with respect to duration and severity of illness and in a normal control group matched for sex, age and educational level. The mean value of ventricular brain ratio (VBR) was significantly higher in schizophrenics than controls. Seven patients (21.2%) who had VBRs exceeding 2 SD of the control mean showed a significantly longer duration of illness than the other schizophrenics with significantly higher scores on the subscales alogia, effective flattening and attentional impairment of SANS, on the scales self-care and behaviour in crises and emergencies of DAS, on the scales rhythm, tactile, visual, reading, arithmetic, memory and left hemisphere of LNNB, and on the subtests arithmetic, digit span, digit symbol and block design of WAIS. These results confirm earlier reports of an enlargement of lateral cerebral ventricles in a subset of schizophrenics, and its association with a higher degree of cognitive and neuropsychological impairment, social maladjustment and defectual symptomatology. Moreover, they suggest that the neuropathological process likely to underlie the increase of cerebral ventricular size progresses during the course of the illness rather than predating its onset.

Melatonin and LSD induce similar retinal changes in the frog

This work is based on histological examination with the light microscope of Nissl-stained frogs’ retinae following melatonin and lysergic acid die~ylamide (LSD) administ~tion. In a previous paper (Kemali et al. 1983) we have demonstrated with the light microscope that administration of LSD induced in the frog retina a modification of the pigment screening (PS) pattern through some unknown mechanism. PS is a phenomenon encountered in the retina of low vertebrates and involves the migration of melanin granules from the retinal pigment epithelium in response to illumination changes. In the light, melanin granules disperse along the pigment epithelium processes, which protrude among the outer segments of the photoreceptors. In the dark, on the other hand, melanin granules aggregate within the cell body of the pigment epithelium (for review see Nguyen-Legros 1978). In another earlier paper (Kemali et al. 1984) we have demons~ated that the adminis~ation of dopaminergic agents to the frog did not induce any substantial modifications of this PS pattern, suggesting that dopamine is probably not directly involved in this retinomotor phenomenon, The aim of the present investigation was to

Drugs and the frog retina. Effect of dopaminergic agents on the pigment screening of light- and dark-adapted frogs.

This is a study, using the light and electron microscope, of the action of a dopamine agonist (apomorphine) and of a dopamine antagonist (haloperidol) on the retinal pigment screening (PS) of light- and dark-adapted frogs. Pigment screening is a phenomenon which consists of the migration of melanin granules into processes of the pigment epithelium that extend between photoreceptors, in response to changes in the conditions of illumination. In the light the pigment migrates vitreally , in the dark it aggregates sclerally . A single intravenous injection of apomorphine (0.15 mg/kg) and of haloperidol (1 mg/kg) did not induce substantial modifications in the pattern of pigment screening which was similar to that of controls both in light- and dark-adapted frogs. This suggests that dopamine is probably not directly involved in the phenomenon of pigment screening in the retina of the frog.

Modification of the pigment screening of the frog retina following administration of neuroactive drugs

Pigment screening (PS) occurs in the retina of lower vertebrates and consists of the bidirectional migration (vitreally or sclerally) of melanin granules into processes of the pigment epithelium that extend between photoreceptors, in response to changes in the illumination conditions. We have studied the effect of some neuroactive drugs on the PS of frogs maintained under cyclic lighting conditions or dark-adapted. The drugs, administered intravenously were: lysergic acid diethylamide (LSD), mescaline, d-amphetamine, the LSD analogue lisuride and the LSD derivative 2-bromolysergic acid (BOL). All the drugs used--with the exception of mescaline--modify the bidirectional migration of the pigment induced by the two illumination conditions in a different way. This suggests that in general these substances interact in some way with those processes which normally produce the well-defined PS pattern. It has been possible to discriminate two opposite effects on the retinal PS induced by two chemically related substances (LSD and lisuride) only one of which (LSD) has potent hallucinogenic properties.

Frog retinal pigment screening and lithium.

The effect of the intraperitoneal injection of lithium on the pattern of the pigment screening (PS) of the frog retina has been studied in various illumination conditions. Lithium enhances the PS pattern induced by dark and it substantially modifies the PS pattern induced by the other light conditions. The dark-induced PS pattern is very stable and might be regulated by a single factor. The PS of light-adapted frogs is easily modified by drug administration and probably depends on a variety of factors which may be affected differently by the various injected substances. The possibility that lithium, melatonin and darkness might act in the same way or on the same system which regulates the PS in dark-adaptation must not be disregarded.