Date of Completion

Spring 5-1-2008

Thesis Advisor(s)

Catherine Proenza

Honors Major

Physiology and Neurobiology


Life Sciences | Neuroscience and Neurobiology | Physiology


The sinoatrial node is known as the pacemaker of the heart. It controls the rate at which action potentials are generated and propagate through the sinoatrial myocytes. This thesis is an attempt to identify the colocalization of a specific ion channel (HCN4 channel) with a class of scaffolding protein (MAGUK proteins) within the sinoatrial myocyte. The colocalization of these two variables was performed using immunocytochemistry on murine sinoatrial myocytes and experimental results revealed the existence of a strong colocalization between the two variables. Images collected from the confocal microscope and analyzed using ImageJ software revealed a strong dependent correlation between the pixel intensities (488 beam-green, 633 beam-blue). The colocalization of HCN4 channels with a specific MAGUK scaffolding protein could lead to further research into a possible complex among the HCN4 channels and β1ARs within the sinoatrial myocytes. Although automaticity of the heart has been identified, the precise molecular mechanisms involved in generating the involuntary contractions are still being investigated.