Connections of hypothalamic paraventricular neurons with the dorsal medial thalamus and neurohypophysis: an electrophysiological study in the rat.
Connections between the hypothalamic paraventricular nucleus (PVN) and thalmic paraventricular nucleus ( PVT ) were examined using electrophysiological methods. Efferent projections of adjacent PVN cells were defined on the basis of antidromic activation from either PVT (n = 12) or neurohypophyseal (n = 38) stimulation; antidromic activation from both sites (n = 3) suggested that some PVN cells project both to the PVT and to the neurohypophysis. PVT stimulation evoked only weak orthodromic responses from 21% of PVN neurohypophyseal neurons, whereas short latency, high probability orthodromic responses were observed from 43% of PVN non-neurosecretory neurons. These data indicate reciprocal PVN- PVT connections and suggest that PVT afferents preferentially innervate non-neurosecretory PVN cells.
D000818:Animals; D004594:Electrophysiology; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D010904:Pituitary Gland, Posterior / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000502:physiology; D013787:Thalamic Nuclei / Q000502:physiology*