Developmental changes in GABAergic neurotransmission to presympathetic and cardiac parasympathetic neurons in the brainstem

Olga Dergacheva , Carie R. Boychuk , David MendelowitzJournal of Neurophysiology Published 1 August 2013Vol. 110no. 672-679DOI: 10.1152/jn.01054.2012. This article was interesting because it investigated how postnatal development altered gabaergic neurotransmission specifically, the effects on parasympathetic cardiac and presympathetic neurons in the brainstem. This group was interested in how hypoxia and hypercapnia (H/H) may play role in this. They used retrograde labelling with CTB injected in the T2-T4 region of the spinal cord. Then at certain days postnatal p5, p20, p30 and they looked at GABAergic neurotransmission and how it was altered by hypoxia and hypercapnia. In the parasympathetic cardiac vagal neurons there was IPSCs in response to strychnine in P5, P20, and P30. However, the P20 had increased frequency and amplitude of IPSCs than the other groups. As for the cardiac parasympathetic neurons on the P20 frequency was altered in under control conditions when compared to the P5 and P30. In response to H/H in the P5 and P30 the IPSCs were reversed however in the P20 frequency and amplitude IPSC not altered for presympathetic neurons. H/H decreased IPSC frequency in P5,P20, and P30. In only decreased the amplitude in the P20. These data demonstrate P20 is an important developmental stage for parasympathetic and sympathetic development. The reason why this study is so important is because this age in rats is equivalent to the age when children tend to develop SIDS. This increased sensitivity to hypoxia/ hypercapnia may be a possible reason why SIDS. -MD