Activation of paraventricular nucleus neurones by the dorsomedial hypothalamus via a tachykinin pathway in rats.
The dorsomedial hypothalamus (DMH) innervates the paraventricular nucleus (PVN) with substance P (SP) immunoreactive neurones. The PVN itself powerfully influences both the neuroendocrine and the cardiovascular systems. In this in vitro study, we examine the DMH-to-PVN pathway electrophysiologically. Glutamate application to the DMH increased action current frequency in the PVN. This effect was prevented by the glutamate antagonist kynurenic acid or by synaptic block with a high-Mg(2)(+) low-Ca(2)(+) buffer solution. Crucially, the selective tachykinin NK1 receptor antagonist L-703606 also inhibited DMH-to-PVN neurotransmission. Thus we show, for the first time, an excitatory connection between the DMH and PVN that uses tachykinin NK1 receptors. This pathway may be important for the hypothalamic control of neuroendocrine and/or cardiovascular function.
Womack
Matthew D
MD
Department of Veterinary Preclinical Sciences, Veterinary Sciences Building, Brownlow Hill & Crown Street, University of Liverpool, Liverpool L69 7ZJ, UK.
Barrett-Jolley
Richard
R
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004302:Dorsomedial Hypothalamic Nucleus / Q000502:physiology*; D018698:Glutamic Acid / Q000494:pharmacology; D009474:Neurons / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D011812:Quinuclidines / Q000494:pharmacology; D051381:Rats; D018040:Receptors, Neurokinin-1 / Q000502:physiology*; D013373:Substance P / Q000502:physiology*
D011812:Quinuclidines; D018040:Receptors, Neurokinin-1; C076851:L 703606; D013373:Substance P; D018698:Glutamic Acid