engleski

Atropine-mydriasis NO-system Dependent, L-NAME- miosis, L-arginine-miosis, and Counteraction by Stable Gastric Pentadecapeptide BPC 157, in Living Rats

In living rats, atropine-mydriasis would depend on NO-related mechanisms in a particular way: both L- NAME, a NOS-blocker and L-arginine, a NOS- substrate wouldexhibit a miotic effect, not yet described ; the atropine-mydriasis and L-NAME- and L-arginine-miosis, could consequently be counteracted by BPC 157 due to its interactions with the NO-system and sphincter function. We administraded BPC 157 (10µg, 10ng, 10pg/kg), L- NAME (5mg/kg), and/or L-arginine (100mg/kg) alone/together intraperitoneally in healthy rats (miosis-studies) or at 30 min after 1% atropine/2drops/eye (mydriasis-studies). BPC 157 does not alter normal pupil diameter while miosis occured promptly after both L-NAME and L-arginine, lasting for more than 3h, when they were given alone. When L-NAME+L-arginine were given together, this miosis was shorter, suggesting that their separate miotic effects are competitive and may antagonize each other. These L-NAME-/L-arginine- effects were both shortened in rats that received BPC 157. In case of maximal atropine-mydriasis all of the agents, BPC 157, L-NAME and L-arginine, induce a counteraction, commencing sooner in BPC 157-rats, but all of the agents lead to completely blunted atropine-mydriasis returning to regular pupil size hours sooner than in atropine-rats which received saline. Concluding, BPC 157 may counteracted those effects due to its interactions with the NO-system and sphincter function. Supported by Grant 108-1083570-3635, Croatia.

BPC 157 ; Atropine-mydriasis ; L-NAME-miosis ; L-arginine-miosis ; Pentadecapeptide ; Rats

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