ATP potentiates neurotransmission in the rat trigeminal subnucleus caudalis.
Ionotropic purine receptors (P2X) have been implicated in nociceptive neurotransmission. In this study, we examine the actions of the P2X receptor agonist alpha,beta methylene adenosine 5'-triphosphate on excitatory neurotransmission in neurons in the deep and superficial laminae of the trigeminal spinal subnucleus caudalis (Vc), which receives nociceptive inputs from the craniofacial region. Alpha, beta methylene adenosine 5'-triphosphate caused an increase in spontaneous excitatory neurotransmission (miniature excitatory postsynaptic currents) in neurons in deep but not superficial laminae of Vc; this effect could be inhibited by the P2X receptor antagonist 2,3-O-2,4,6-trinitrophenyl-ATP. Conversely, the TRPV1 agonist capsaicin caused an increase in miniature excitatory postsynaptic currents in neurons in the superficial but not deep laminae. These data suggest that alpha,beta methylene adenosine 5'-triphosphate acts on presynaptic terminals to increase glutamatergic neurotransmission in deep Vc neurons.
Jennings
Ernest A
EA
Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria, Australia. e.jennings@unimelb.edu.au
Christie
MacDonald J
MJ
Sessle
Barry J
BJ
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D018712:Analgesics, Non-Narcotic / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002211:Capsaicin / Q000494:pharmacology; D004347:Drug Interactions; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects*; D014275:Trigeminal Caudal Nucleus / Q000166:cytology* / Q000187:drug effects
D018712:Analgesics, Non-Narcotic; D018691:Excitatory Amino Acid Antagonists; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002211:Capsaicin