Paraventricular nucleus of the hypothalamus glutamate neurotransmission modulates autonomic, neuroendocrine and behavioral responses to acute restraint stress in rats

• Published in: European neuropsychopharmacology Vol. 23; no. 11; pp. 1611 - 1622
• Main Authors: Busnardo, Cristiane, Alves, Fernando H.F, Crestani, Carlos C, Scopinho, América A, Resstel, Leonardo B.M, Correa, Fernando M.A
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2013
• Subjects: Animals; Anxiety; Arterial Pressure - drug effects; Arterial Pressure - physiology; Cardiovascular; Corticosterone - blood; Elevated plus maze test; Excitatory Amino Acid Antagonists - administration & dosage; Excitatory Amino Acid Antagonists - pharmacology; Heart Rate - drug effects; Heart Rate - physiology; HPA axis; Internal Medicine; Isoquinolines - administration & dosage; Isoquinolines - pharmacology; Male; Maze Learning - drug effects; Maze Learning - physiology; Microinjections; NMDA glutamate receptors; Non-NMDA glutamate receptors; Paraventricular Hypothalamic Nucleus - drug effects; Paraventricular Hypothalamic Nucleus - physiology; Paraventricular Hypothalamic Nucleus - physiopathology; Psychiatry; PVN; Quinoxalines - administration & dosage; Quinoxalines - pharmacology; Rats; Receptors, Glutamate - physiology; Receptors, N-Methyl-D-Aspartate - antagonists & inhibitors; Receptors, N-Methyl-D-Aspartate - physiology; Restraint, Physical; Skin Temperature - drug effects; Skin Temperature - physiology; Stress; Stress, Psychological - physiopathology; Synaptic Transmission - physiology; Non-NMDA glutamate receptors; NMDA glutamate receptors; Cardiovascular; Elevated plus maze test; PVN; Anxiety; HPA axis; Stress
• ISSN: 0924-977X; 1873-7862
• DOI: 10.1016/j.euroneuro.2012.11.002

Abstract In the present study, the involvement of paraventricular nucleus of the hypothalamus (PVN) glutamate receptors in the modulation of autonomic (arterial blood pressure, heart rate and tail skin temperature) and neuroendocrine (plasma corticosterone) responses and behavioral consequences evoked by the acute restraint stress in rats was investigated. The bilateral microinjection of the selective non-NMDA glutamate receptor antagonist NBQX (2 nmol/ 100 nL) into the PVN reduced the arterial pressure increase as well as the fall in the tail cutaneous temperature induced by the restraint stress, without affecting the stress-induced tachycardiac response. On the other hand, the pretreatment of the PVN with the selective NMDA glutamate receptor antagonist LY235959 (2 nmol/100 nL) was able to increase the stress-evoked pressor and tachycardiac response, without affecting the fall in the cutaneous tail temperature. The treatment of the PVN with LY235959 also reduced the increase in plasma corticosterone levels during stress and inhibited the anxiogenic-like effect observed in the elevated plus-maze 24 h after the restraint session. The present results show that NMDA and non-NMDA receptors in the PVN differently modulate responses associated to stress. The PVN glutamate neurotransmission, via non-NMDA receptors, has a facilitatory influence on stress-evoked autonomic responses. On the other hand, the present data point to an inhibitory role of PVN NMDA receptors on the cardiovascular responses to stress. Moreover, our findings also indicate an involvement of PVN NMDA glutamate receptors in the mediation of the plasma corticosterone response as well as in the delayed emotional consequences induced by the restraint stress.