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An Adenosine A(2A) Agonist Injected in the Nucleus of the Solitary Tract Prolongs the Laryngeal Chemoreflex by a GABAergic Mechanism in Decerebrate Piglets

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Journal Exp Physiol
Specialty Physiology
Date 2010 Apr 27
PMID 20418346
Citations 7
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Abstract

Hyperthermic prolongation of the laryngeal chemoreflex (LCR) in decerebrate piglets is prevented or reversed by GABA(A) receptor antagonists and adenosine A(2A) (Ad-A(2A)) receptor antagonists administered in the nucleus of the solitary tract (NTS). Therefore, we tested the hypothesis that enhanced GABA(A) activity and administration of the Ad-A(2A) agonist, CGS-21680, would prolong the LCR in normothermic conditions. We studied 46 decerebrate piglets ranging from 3 to 8 postnatal days of age. Focal injection into the NTS of 100 nl of 0.5 m nipecotic acid, a GABA reuptake inhibitor, significantly (P < 0.05) prolonged the LCR in normothermic conditions in 10 of 11 animals tested. Injecting 100 nl of 5-12.5 microm CGS-21680 unilaterally or bilaterally into the NTS also prolonged the LCR in normothermic conditions (n = 15), but the effect was smaller than that of unilateral injection of nipecotic acid. Systemic administration of the GABA(A) receptor antagonist, bicuculline, prevented the CGS-21680-dependent prolongation of the LCR in normothermic animals (n = 11). We conclude that thermal prolongation of the LCR depends on a thermally sensitive process or set of neurons in the NTS, which, when activated by elevated brain temperature, enhances adenosinergic and GABAergic function in the region of the NTS. These results emphasize the importance of a thermally sensitive integrative site in the dorsal medulla that, along with sites in the ventral medulla, determine the response to laryngeal chemoreflex stimulation.

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References
1.
Xia L, Damon T, Leiter J, Bartlett Jr D . Focal warming in the nucleus of the solitary tract prolongs the laryngeal chemoreflex in decerebrate piglets. J Appl Physiol (1985). 2006; 102(1):54-62. DOI: 10.1152/japplphysiol.00720.2006. View

2.
Petrillo G, Glass L, Trippenbach T . Phase locking of the respiratory rhythm in cats to a mechanical ventilator. Can J Physiol Pharmacol. 1983; 61(6):599-607. DOI: 10.1139/y83-092. View

3.
Bohm I, Xia L, Leiter J, Bartlett D . GABAergic processes mediate thermal prolongation of the laryngeal reflex apnea in decerebrate piglets. Respir Physiol Neurobiol. 2006; 156(2):229-33. DOI: 10.1016/j.resp.2006.10.005. View

4.
Martin R, Wilson C, Abu-Shaweesh J, Haxhiu M . Role of inhibitory neurotransmitter interactions in the pathogenesis of neonatal apnea: implications for management. Semin Perinatol. 2004; 28(4):273-8. DOI: 10.1053/j.semperi.2004.08.004. View

5.
Graves C, Glass L, Laporta D, Meloche R, Grassino A . Respiratory phase locking during mechanical ventilation in anesthetized human subjects. Am J Physiol. 1986; 250(5 Pt 2):R902-9. DOI: 10.1152/ajpregu.1986.250.5.R902. View