$346 P.6 Other topics Since 7-NI blocked the development of the behavioural signs of withdrawal when administered before, but not during withdrawal, it could be presumed that this effect is not caused by NOS inhibition, but by some other mechanism, probably by decreased ethanol clearance. This hypothesis is supported by the fact that L-NA had no efffect on ethanol withdrawal syndrome. 1).6 Other topics • Excess TPH 17 779C allele in surviving cotwins of monozygotic twin suicide victims A. Roy, G. Rylander, M. Asberg, C. Mazzanti, D. Goldman, D. Nielsen. Department of Veterans Affairs~NewJersey Health Care Sys- tems, Karolinska Institute and NIAAA, NIH, USA Objective: To evaluate the relationship of the tryptophan hydroxylase (TPH) and serotonin transporter (5-HTTLPR) genotypes to suicidality by the study of the study of surviving monozygotic (MZ) cotwins of twins who committed suicide. Method: Twenty-four surviving Swedish MZ twins whose MZ cotwins had committed suicide were compared to 158 demographically sampled Swedish general population controls for TPH and 5-HTTLPR alleles. Results: The living MZ cotwins of suicide victims had a significantly higher TPH 17 779C allele frequency than controls. No significant difference was observed for 5-HTTLPR alleles. Conclusion: The 17 779C allele of the TPH gene is associated with an increased risk of suicide. • Gerontopaychiatric networking in rural areas W. Schreiber I , Th. Schneyer ?', R. Schlichting3, T. Becket?, J.-C. Kfieg 1. 1Dep. of Psychiatry and Psychotherapy; 2Dep. of Psychotherapy and Behavioral Medicine, Philipps-Unioersity Marburg," 3Dep. of Geriatric Care, County of Marburg-Biedenkopf, Germany Study Purpose: The setup of adequate gerontopsychiatric care in rural areas requires a multilateral approach which enables its members to respond on the spot, in a decentralized manner, to the needs of the individual patient. When establishing such a gerontopsychiatric network, however, one has to consider not only the individual demands of the patient, but also the structural and technical competency of all professional and non-professional caregivers involved. The aim of our present study was, therefore, to provide a respective characterization of the individual participants within a gerontopsychiatric network in a rural area, taking the German county of Marburg-Biedenkopf in Upper Hessia as an example. Methods: All registered general practioners (GP) and specialists for internal medicine, psychiatry and psychotherapy as well as all in- and outpatient clinics, day and night clinics, senior residences, nursing homes and outpatient geriatric services in the county were asked to fill out a standardized questionnaire. The main alms of this questionnaire were 1) to draw a profile of the geriatric care offered by the different suppliers, 2) to appraise the respective need for psychiatric help among their individual client61e, 3) to assess the nature and degree of their patients' specific impairments, 4) to elucidate their present state of cooperation within the network, and 5) to evaluate their respective requests for improving common gerontopsychiatric care. Results: Of the 391 questionnaires sent out, we had a mean response rate of 34%, differing from 12% for the GP up to 91% for the senior residences. Among the different geriatric services, only some hospitals and senior residences offered the whole spectrum of gerontopsychiatric care, ranging from individual visits at the patient's home to full-time inpatient nursing. Nearly two thirds of the psychiatric and psychothera- peutical patients, but only about 10% of GP's patients were indicated as needing continous psychiatric and/or neurological treatment, i.e. at least once per quarter of a year. Concerning their individual impairments, a vast majority of the patients under psychiatric and psychotherapeutical treatment was reported to show affective symptoms, while patients treated in hospitals, part-time clinics and senior residences mainly displayed financial problems and social isolation along with cognitive impairment. Deficiencies in professional cooperation were particularly evident regarding the interaction of both senior residences and spe- cialists for psychiatry and psychotherapy with all other professional and non-professional caregivers, Concerning individual requests for an improvement of gerontopsychiatric care, senior residences were mainly interested in an enlargement of their individual staff and an economical endowment, while outpatient gerontopsychiatric services stressed the need for intensified education and supervision. Conclusions: Our study provides an overall profile of the individual needs &both professional and non-professional gerontopsychiatric care- givers in a rural area. The realization of these heterogenous expectations constitutes market-like dynamics of gerontopsychiatric demand and supply which require the establishment of flexible and adaptive network structures. • Iontophoretic study of dopamlne and its antagonists on motor cortical neuron activity elicited by stimulation of ventrolateral nucleus of the cat K. Huda, K. Matsunami °, T.L. Salunga, X.E. Han, S.A. Chowdhury. Department of Neurophysiology, Institute of Equilibrium Research, Gifu University School of Medicine, Tsukasamachi40, Gifu, 500-8705, Japan Dopamine has long been considered as an important neuronal transmit- ter/neuromodulator, playing an essential role for motor behavior, recog- nition and working memory. In this context, DAergic signal transduction system has been a keen interest in relation to cerebral cortical functions. The anatomico-pysiological studies revealed that the mesencephalic DAergic system appeared to be prepotent in respect to its widespread distribution in almost all cortical areas of rat, cat and monkey, with the highest density in the motor cortex. This implies the crucial role of DA for motor functions in the forehrain. In our previous study, we demonstrated that the transcallosal neuronal activity, which is mediated by glutaminergic excitatory callosal afferents, was suppressed by the application of DA, and this suppression was restored by the application of D1 and D2 antagonists (1). Then we started the present experiments with the expectation that the cortical response to VL thalamic afferents, which is also excitatory in nature and has a pivotal role in motor behaviors, could be suppressed by application of DA. Methods: Experiments were conducted with adult cats with mini- mized discomfort in accordance with NIH guidelines. The cat was first anesthetized with combination of sodium pentobarbital (20 mg/kg, body weight, i.p) and ketamine hydrochloride (10 mg/kg, i.m). Thereafter, the cephalic vein was cannulized with a fine silicon tube to keep a deep and stable anesthetic conditions with additional doses of sodium pentobarbital (1 mg/kg body weight/hr). Artificial ventilation was con- ducted. Body temperature was maintained by a heat pad. After setting stimulating electrodes in the VL of the thalamus and in the pyramidal tract (PT) to identify PT neurons (PTNs), neruonal activity responding to VL stimulation was recorded by the center barrel of a multi-barrel glass microelectrode. DA and D1 antagonist SCH 23390 (SCH), D2 antagonist sulpiride (SUL) and D1/D2 antagonist haloperidol (HAL) were iontophoretically applied through peripheral barrels. Effects of each drug were estimated by the change of the number of spikes evoked by 20 trials of VL stimulation. ANOVA (Bonferroni/Dunn; StatView 4.0) was used for statistical analysis. Results: In most cases, the spike number changed significantly, whereas their latencies remained unchanged. DA predominantly de- creased the firing rate (p < 0.05). By contrast, both D1 and D2 antagonist restored the DA induced effects almost to the control level. Alternatively, opposite effects of increase in the spike number were also elicited in some neurons to DA manipulation, but the change was not significant