LHRH-immunoreactive neurons in the pterygopalatine ganglia of voles: a component of the nervus terminalis?

Cranial tissue from adult and neonatal voles was examined with immunocytochemical techniques to determine the distribution of luteinizing hormone-releasing hormone-immunoreactive (LHRH-ir) neurons in extracerebral structures. The overall distribution of the LHRH-ir portion of the nervus terminalis in the nasal and extracranial cavities was comparable to that of other rodents. However, we observed a unique association of LHRH-ir neurons with the pterygopalatine ganglia of neonatal and adult voles. We also found LHRH-ir fibers in nasopalatine nerves, and trigeminal nerves and ganglia of neonatal voles. We speculate that these neurons may influence the autonomic control of the vascular pump in the vomeronasal organ.