[Drug use and dependence in schizophrenia]. / Consumo y dependencia de drogas en la esquizofrenia.

Drug dependence is common in schizophrenia. Two main models explain this association: drugs precipitate psychosis in a vulnerable subject, and drugs use to self-medicate positive and negative symptoms and neuroleptics side effects. We investigated the prevalence of psychoactive substance use and dependence in schizophrenia and its association with the subtype of schizophrenia. The sample consisted of 56 outpatients with schizophrenia according to ICD-10, between 18 and 40 years, and a control group with 56 subjects with other different disorder. They were evaluated with Addiction Severity Index (ASI) and Positive And Negative Syndrome Scale (PANSS), sociodemographical, clinical and toxicological characteristics were evaluated too. Patients were classified in subtype negative, positive or mixed according to scoring in PANSS. Schizophrenics were reevaluates at six months of development. There were higher cocaine, alcohol, cannabis and nicotine use in schizophrenics. The patients with negative subtype of schizophrenia had more clinical severity, less scoring in alcohol and drugs subscales of ASI, lower prevalence of nicotine dependence and cocaine, amphetamines, cannabis and opioids use. Drugs use were associated with a poor compliance of treatment. Therefore, cannabis and cocaine dependence, regular alcohol use and tobacco use are more prevalent in schizophrenic than control group with other mental disorders. Negative subtype had lower drug use.

The vasoactive intestinal peptide receptor-effector system is developmentally regulated in rat jejuno-ileal epithelial cells.

The specific binding of vasoactive intestinal peptide (VIP) to its specific receptors as well as the stimulatory effect of the neuropeptide on cyclic AMP accumulation were studied in jejuno-ileal epithelial cells from 14-, 20- and 60-day-old rats. The potency and specificity of the VIP receptor-effector system did not vary during development. However, the concentration of VIP receptors and the efficiency of VIP stimulation of cyclic AMP generation increased from suckling to adult conditions, and VIP levels in jejuno-ileal tissue followed a parallel course.

Interaction of insulin with small intestinal epithelial cells from developing rats.

The interaction of insulin with its specific receptors was studied in jejunoileal epithelial cells from 14-, 20-, and 60-day-old rats. Characteristics such as potency and specificity of the insulin receptor system did not vary during development. However, insulin binding decreased with age due to a diminished concentration of insulin receptors, whereas the circulating levels of the hormone followed an inverse evolution. These results support previous suggestions on the potential role of insulin on the mechanisms of differentiation and proliferation of small intestinal mucosa.

Ileal vasoactive intestinal peptide (VIP) levels and VIP receptor/effector system in ileal epithelial cells after colectomy in the rat.

The interaction of VIP (binding to specific receptors and stimulation of cyclic AMP accumulation) with ileal epithelial cells and the levels of the neuropeptide in the ileal segment were determined after colectomy (removal of cecum and colon followed by ileorectal anastomosis) in the rat. The number of VIP receptors (but not the affinity) and the efficiency (but not the potency) of the neuropeptide upon stimulation of cyclic AMP accumulation in ileal epithelial cells increased 21 (but not 7) days after colectomy, whereas VIP ileal levels followed an inverse pattern. These changes could be interpreted in terms of a consequence or a cause of some of the phenomena that appear after colectomy, i.e., chronic watery diarrhea.

Somatostatin inhibits VIP- and isoproterenol-stimulated cyclic AMP accumulation in rat prostatic epithelial cells.

The dual regulation of cyclic AMP accumulation was studied in rat prostatic epithelial cells incubated with somatostatin, vasoactive intestinal peptide (VIP), and the beta-adrenergic agent isoproterenol. Somatostatin noncompetitively inhibited the stimulatory effect of VIP and isoproterenol, but it did not alter basal cyclic AMP levels. In addition to the multifactorial regulation of the cyclic AMP system in rat prostatic epithelium, these results suggest that somatostatin may play a physiological role at this level.

Tissue and plasma distribution of exogenous growth hormone-releasing factor analogue (GRF1-29NH2) after intravenous, subcutaneous and intraperitoneal injection in the rat.

1. The administration of 125I-labelled growth hormone-releasing factor (GRF) analogue 1-29NH2 by intravenous, subcutaneous or intraperitoneal injection to rats leads to rapid (i.v.) or slow (s.c. and i.p.) increases in plasma radioactivity followed by extensive breakdown of the peptide. 2. Tissues possessing GRF-like immunoreactivity such as gastric antrum (but not fundus), duodenum and ileum showed in vitro specific uptake of 125I-GRF probably mediated by vasoactive intestinal peptide (VIP) receptors. 3. Pituitary (the primary target organ for GRF) but neither thyroid nor parathyroid exhibited specific uptake of 125I-GRF.