Adenosine triphosphate as a stimulant for nociceptive and non-nociceptive muscle group IV receptors in the rat.
For cutaneous and articular nociceptors, adenosine triphosphate (ATP) has been shown to be an effective stimulant. The aim of present study was to find out if among muscle afferents ATP-sensitive group IV receptors are present, and if differences in ATP-responsiveness existed between nociceptive and non-nociceptive units. Single fibre activity was recorded from group IV afferents innervating the rat gastrocnemius-soleus muscle. Using mechanical stimuli the fibres were classified as nociceptive or non-nociceptive ones. ATP was injected intramuscularly into the receptive field of the fibre. Results were: (1) ATP at a concentration that is present in muscle cells elicited excitations in 67% of the fibres; (2) ATP excited both nociceptive and non-nociceptive receptors; and (3) the acidity of the ATP solution was not an important factor for the ATP effect.
Reinöhl
Jochen
J
Institut für Anatomie und Zellbiologie, Universität Heidelberg, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany.
Hoheisel
Ulrich
U
Unger
Thomas
T
Mense
Siegfried
S
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects / Q000502:physiology; D009619:Nociceptors / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058848:Receptors, Purinergic P2X4
C548228:P2rx4 protein, rat; D018048:Receptors, Purinergic P2; D058848:Receptors, Purinergic P2X4; D000255:Adenosine Triphosphate