Sympathetic Hyperactivity and Age Affect Segregation and Expression of Neurotransmitters.

Sympathetic neurons of the rat superior cervical ganglion (SCG) can segregate their neurotransmitters and co-transmitters to separate varicosities of single axons. We have shown that transmitter segregation is a plastic phenomenon and that it is correlated with the strength of synaptic transmission. Here, we determined whether sympathetic dysfunction occurring in stress and hypertension was correlated with plastic changes of neurotransmitter segregation. We characterized the expression of the markers, L-glutamic acid decarboxylase of 67 kDa (GAD67) and vesicular acetylcholine (ACh) transporter (VAChT) in the SCG of cold stressed and spontaneously hypertensive rats (SHR). Considering that the SCG comprises a heterogeneous neuronal population, we explored whether the expression and segregation of neurotransmitters would also have an intraganglionic heterogeneous distribution in ganglia of stressed and hypertensive rats. Furthermore, since hypertension in SHR is detected around 8-10 weeks, we evaluated expression and segregation of ACh and GABA in adult hypertensive (12-week old (wo)) and young pre-hypertensive (6-wo) SHR. We found an increase in segregation of ACh and GABA with no change in transmitter expression in ganglia of stressed animals. In contrast, in SHR, there was an increase in GABA expression, although segregation did not vary. Segregation showed a caudo-rostral gradient in controls but not in the ganglia of stressed animals. GABA expression showed a rostro-caudal gradient in adult SHR, which was not present in young 6-wo rats. In young SHR, ACh increased and, unexpectedly, segregation of ACh and GABA was higher than in adults. Data suggest that ACh and GABA segregation increases in acute sympathetic hyperactivity like stress, but does not vary in chronic hyperactivity such as in hypertension. Changes in segregation are age-dependent and might be involved in the mechanisms underlying stress and hypertension.

Gangliosidosis Gm2 por deficiencia de hexosaminidasas A y B: a propósito de un caso / Hexosaminidase A and B deficiency, Gm2 gangliosidoses: apropos of a case

Se describe un paciente masculino de 26 meses de edad, hijo de padres no consanguíneos y quien presentó manifestaciones clínicas, bioquímicas e histopatológicas compatibles con la enfermedad de Sandhoff. Con fines de asesoramiento genético, se discuten las bases genéticas y moleculares que sustentan el diagnóstico diferencial con otras gangliosidosis Gm2

Enfermedad de Fabry: a propósito de una familia / Fabry's disease: a propos of a family

Se describe una paciente de 18 años de edad quien presentó manifestaciones clínicas, bioquímicas e histopatológicas compatibles con la enfermedad de Fabry. La madre y una hermana menor, clínicamente asintomáticas, presentaron niveles enzimáticos que permitieron considerarlas como portadoras; en cambio, la determinación enzimática en el padre y en dos hermanos varones, se relacionó con la ausencia de sintomatología en estos individuos. Se discute la importancia de establecer un diagnóstico de certeza y del estudio familiar, con el fin de poder ofrecer un mejor asesoramiento genético