Possible Interaction: Adenosine and Capsaicin

“ Adenosine release is reduced by intrathecal and neonatal pretreatment with capsaicin but not by intrathecal pretreatment with 6-hydroxydopamine or 5,7-dihydroxytryptamine, indicating that adenosine originates from small-diameter primary afferent neurons but not descending monoaminergic pathways.”

“Results: Adenosine , in the concentration of 100 µM, injected into the femoral artery had an inhibitory effect on the reflex RSNA and BP responses induced by capsaicin.”

“The inhibition of AMP‐ and CPA‐induced airway obstruction by atropine, capsaicin and bilateral vagotomy suggests a neuronal‐dependent mechanism with the particular involvement of capsaicin‐sensitive nerves.”

“Pretreatment with lidocaine, the β-receptor agonist, terbutaline, or the adenosine non-blocking xanthine, enprofylline, inhibited the capsaicine induced inflammatory response.”

“Systemic pretreatment with capsaicin , a neurotoxin selective for small-diameter sensory afferents, markedly reduced the saline-evoked release of adenosine in rat hind paw following spinal nerve ligation.”

“Acute injection of 1% capsaicin to the hind paw of untreated rats also induced adenosine release.”

“Pretreatment with capsaicin , a neurotoxin selective for unmyelinated small diameter primary afferent nerves, markedly reduced the adenosine released by 1.5% formalin and the early phase of release by 5% formalin.”

“In rats treated with capsaicin to destroy sensory neurons, the response to higher doses of adenosine , CPA and NECA, but not IB‐MECA, was significantly inhibited.”

“ Adenosine (1-10 microM) … dose dependently the capsaicin 10 microM)-induced depolarization of myenteric neurons, but did not inhibit the depolarizing response to exogenous substance P. The adenosine P1 receptor antagonist, 8-phenyltheophylline (1-10 microM), antagonized the inhibitory effect of adenosine (1-10 microM) on the mechanical responses.”

“ Adenosine (10-100 microM) suppressed the contractile response to a threshold concentration of capsaicin (1 microM) while leaving the contractile response to a submaximal concentration of substance P (1 nM) and acetylcholine (0.1 microM) intact.”

“Calcitonin gene-related peptide, adenosine 5'-triphosphate, and adenosine mimicked the inhibitory action of capsaicin on nerve stimulation in all groups, while substance P was without effect.”

“These results suggest that senna or its metabolites may cause a sensory neuropathy of mesenteric resistance vessels and that calcitonin gene-related peptide, adenosine 5'-triphosphate, and adenosine , but not substance P, are possible candidates as mediators of the inhibitory effects induced by capsaicin.”

“Exposure of dorsal, but not ventral, spinal cord synaptosomes to capsaicin produced a dose- and Ca++-dependent release of adenosine , which was reduced by capsaicin pretreatment (neonatal and adult) and inhibition of ecto-5'-nucleotidase.”

“Intrathecal capsaicin also inhibited morphine-evoked release of adenosine in vivo.”