biostudies-literatureUnknownTompkins JDNHLBI NIH HHSNIH HHSIntrinsic cardiac neurons (ICNs) play a crucial role in the proper functioning of the heart; yet a paucity of data pertaining to human ICNs exists. We took a multidisciplinary approach to complete a detailed cellular comparison of the structure and function of ICNs from mice, pigs, and humans. Immunohistochemistry of whole and sectioned ganglia, transmission electron microscopy, intracellular microelectrode recording and dye filling for quantitative morphometry were used to define the neurophysiology, histochemistry, and ultrastructure of these cells across species. The densely packed, smaller ICNs of mouse lacked dendrites, formed axosomatic connections, and had high synaptic efficacy constituting an obligatory synapse. At Pig ICNs, a convergence of subthreshold cholinergic inputs onto exbioRxiv : the preprint server for biology2024.04.04.588174https://www.ebi.ac.uk/biostudies/studies/S-EPMC11030249biostudies-literatureComparative specialization of intrinsic cardiac neurons in humans, mice, and pigs.PMC11030249P01 HL164311OT2 OD023848OT2 OD026585Patel JCCho YArdell JLHoover DBSmith EHShivkumar KBiscola NPAjijola OATompkins JDHavton LAfalseComparative specialization of intrinsic cardiac neurons in humans, mice, and pigs.Intrinsic cardiac neurons (ICNs) play a crucial role in the proper functioning of the heart; yet a paucity of data pertaining to human ICNs exists. We took a multidisciplinary approach to complete a detailed cellular comparison of the structure and function of ICNs from mice, pigs, and humans. Immunohistochemistry of whole and sectioned ganglia, transmission electron microscopy, intracellular microelectrode recording and dye filling for quantitative morphometry were used to define the neurophysiology, histochemistry, and ultrastructure of these cells across species. The densely packed, smaller ICNs of mouse lacked dendrites, formed axosomatic connections, and had high synaptic efficacy constituting an obligatory synapse. At Pig ICNs, a convergence of subthreshold cholinergic inputs onto ex2024-01-01T00:00:00Z2024 Apr2026-04-08T19:47:46.047Z2026-04-08T14:32:57.99ZS-EPMC110302493864517510.1101/2024.04.04.588174