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Cardiovascular effects of L-glutamate microinjection in the supraoptic nucleus of unanaesthetized rats.
- Source :
-
Neuropharmacology [Neuropharmacology] 2007 May; Vol. 52 (6), pp. 1378-84. Date of Electronic Publication: 2007 Feb 04. - Publication Year :
- 2007
-
Abstract
- We report on the cardiovascular effects of L-glutamate (L-glu) microinjection in the hypothalamic supraoptic nucleus (SON) as well as possible receptor and mechanisms involved. Microinjection of L-glu in 100 nL in the SON caused dose-related pressor and bradycardic responses in unanesthetized rats. Responses were markedly reduced in urethane-anesthetized rats. The response to L-glu 10 nmol was blocked by local pretreatment with 2 nmol of the non-NMDA-receptors antagonist NBQX and not affected by 2 nmol of the selective NMDA-receptor antagonist LY 235959, suggesting that non-NMDA receptors mediate these responses. The pressor and bradycardic response to L-glu was potentiated by intravenous pretreatment with the ganglion blocker pentolinium and was blocked by intravenous pretreatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP, suggesting involvement of circulating vasopressin in this response. Additionally L-glu microinjection into the SON increased plasma vasopressin levels (control: 1.3 +/- 0.2 pg/mL, n = 6; L-glu: 14.7+/-2.3 pg/mL, n=6). In conclusion the results suggest that pressor responses to SON microinjection of L-glu are caused by activation of non-NMDA glutamate receptors and mediated by vasopressin release into systemic circulation.
- Subjects :
- Animals
Arginine Vasopressin analogs & derivatives
Arginine Vasopressin blood
Arginine Vasopressin pharmacology
Blood Pressure drug effects
Excitatory Amino Acid Antagonists pharmacology
Ganglionic Blockers pharmacology
Glutamic Acid administration & dosage
Heart Rate drug effects
Isoquinolines pharmacology
Male
Microinjections
Pentolinium Tartrate pharmacology
Quinoxalines pharmacology
Rats
Rats, Wistar
Glutamic Acid pharmacology
Supraoptic Nucleus physiology
Vasopressins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0028-3908
- Volume :
- 52
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Neuropharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 17367824
- Full Text :
- https://doi.org/10.1016/j.neuropharm.2007.01.011