RESUMEN
The influence of acute methamphetamine treatment on serotonin-like immunoreactive axons was studied in the rat forebrain. Animals, sacrificed 90 min after i.p. injection of methamphetamine (16 mg/kg) or saline, were processed for immunocytochemistry using serotonin antiserum. The numerical density of immunoreactive boutons of terminals and varicosities was quantitatively analyzed by a computer-assisted image analyzer. Compared with the control, administration of methamphetamine caused varying degrees of reduction in the numerical density in several forebrain regions. A high decrement (over -90%) was found in deep layers of the cerebral cortex, striatum and thalamic paraventricular nucleus, while a less prominent reduction (about -50%) was seen in such regions as the suprachiasmatic nucleus and basolateral amygdaloid nucleus. Moreover, superficial layers of the cerebral cortex contained uncommon features of immunopositive axons which were characterized by intensely stained fibers with large varicosities. The results suggest that the rat forebrain contains at least two types of serotonin nerves, one very sensitive to methamphetamine and another relatively insensitive or resistant to it.
Asunto(s)
Lóbulo Frontal/metabolismo , Metanfetamina/farmacología , Serotonina/metabolismo , Animales , Lóbulo Frontal/citología , Lóbulo Frontal/efectos de los fármacos , Inmunohistoquímica , Masculino , Ratas , Ratas EndogámicasRESUMEN
Heterogeneity of adult rat neostriatum has been studied by fluorescence histochemistry. The distribution of dopamine nerve fibers and terminals, known normally to be homogeneous, tended to become heterogeneous after administration of methamphetamine or reserpine. Both drugs caused mosaic formations of fluorescent dopamine axons and terminals, though a minor difference was present in the pattern of distribution. The results indicate that the striatum possesses at least two types of dopamine nerve terminals, sensitive and relatively insensitive for the two catecholamine depletors.
