Control of cardiovascular function

The autonomous nervous system has a central role in the control and co-ordination of the cardiovascular system in all vertebrates. This review summarizes current knowledge and the role of the autonomic nervous system in the control of cardiovascular system in fish. Special focus is given to the pacemaker domain in the heart through the expression of the homeodomain transcription factor islet1, Hyperpolarization-activated Cyclic Nucleotic-gated (HCN) channel genes and the immunohistochemistry of HCN isoforms including the location of intracardiac neurons (ICNs) that are found in the sinoatrial region. Cardiac pacemaking is modulated by sympathetic and parasympathetic pathways and the ICNs that project back to central nervous system and provide a link between them.