RESUMEN
In order to delimit the supra-brainstem structures that are activated during the sleep-waking cycle, we have examined c-fos immunoreactivity in four groups of polygraphically recorded cats killed after 3 h of prolonged waking (W), slow-wave sleep (SWS), or paradoxical sleep (PS), following microinjection of muscimol (a gamma-aminobutyric acid, GABA agonist) into the periaqueductal grey matter and adjacent areas [Sastre et al. (1996), Neuroscience, 74, 415-426]. Our results demonstrate that there was a direct relationship between a significant increase in c-fos labelling and the amount of PS in the laterodorsalis tegmenti in the pons, supramamillary nucleus, septum, hippocampus, gyrus cingulate, amygdala, stria terminalis and the accumbens nuclei. Moreover, in all these structures, the number of Fos-like immunoreactive neurons in the PS group was significantly higher (three to 30-fold) than in the SWS and W groups. We suggest that the dense expression of the immediate-early gene c-fos in the rhinencephalon and striatum may be considered as a tonic component of PS at the molecular level and that, during PS, the rhinencephalon and striatum are the main targets of an excitatory system originating in the pons.
Asunto(s)
Cuerpo Estriado/metabolismo , Vías Olfatorias/metabolismo , Proteínas Proto-Oncogénicas c-fos/biosíntesis , Sueño REM/fisiología , Vigilia/fisiología , Animales , Gatos , Corteza Cerebral/química , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Cuerpo Estriado/química , Cuerpo Estriado/citología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/análisis , Proteínas de Unión al ADN/análisis , Femenino , Agonistas del GABA/farmacología , Genes Inmediatos-Precoces/fisiología , Hipotálamo/química , Hipotálamo/citología , Hipotálamo/metabolismo , Sistema Límbico/química , Sistema Límbico/citología , Sistema Límbico/metabolismo , Masculino , Microinyecciones , Muscimol/farmacología , Vías Nerviosas , Vías Olfatorias/química , Vías Olfatorias/citología , Sustancia Gris Periacueductal/química , Sustancia Gris Periacueductal/citología , Sustancia Gris Periacueductal/metabolismo , Puente/química , Puente/citología , Puente/metabolismo , Proteínas Proto-Oncogénicas c-fos/análisis , Sueño/efectos de los fármacos , Sueño/fisiología , Sueño REM/efectos de los fármacos , Tálamo/química , Tálamo/citología , Tálamo/metabolismo , Factores de Transcripción/análisis , Vigilia/efectos de los fármacosRESUMEN
Chronic pontile cats (without hypothalamo-hypophysis) were kept during 4 days at central T (TC) between 37.5 and 30.8 degrees C at stable ambiant T (TA) between 28.5 and 23 degrees C. The vasomotor index of the forepaw was chosen for studying change in vasomotricity. Small and slow variations of TA (+1.5 degrees C) around 27 degrees C were followed by thermoregulatory response since a progressive decrease of TA under 27 degrees C led to vasoconstriction and increase of TC while progressive increase of TA above 27 degrees C led to vasodilatation and decrease of TC. However rapid and large decrease of TA under 27 degrees C (24-23 degrees C) led to the expected hypothermia with decrease of TC but without vasoconstriction. Paradoxical sleep (PS) amounts were strongly correlated with TC. At TC above 35.5 degrees C PS was almost totally suppressed while it increased significantly under 35 degrees C (Q10 = 0.10). Under 35 degrees C at stable TC and TA, PS occurred with an endogenous circahoral rhythm which did not vary significantly between 35 and 32 degrees C. These results strongly suggest that in pontile cats, PS is both gated and regulated by TC, while TC is regulated by pontobulbar vasomotor systems in response to TA. The putative role of the ventro-lateral medulla, in controlling both vasomotricity, TC and the excitability of the locus coeruleus is discussed in relation with PS.