[Effect of adenosine and its analogues on microvascular leakage in the rat trachea].
We examined the effects of adenosine and its analogues on vascular permeability in rat trachea using Evans blue dye as a marker for plasma leakage. Inhalation of N6-2-(4-aminophenyl) ethyladenosine (APNEA), a specific A 3 receptor agonist, increased microvascular leakage in a dose-dependent manner, but adenosine, [R]-N6-(1-Methyl-2-phenylethyl) adenosine (R-PIA), aspecific A 1 receptor agonist, and 5'-(N-ethyl-carboxamide) adenosine (NECA), a specific A 2 receptor agonist, had no effect. Inhalation of capsaicin increased vascular permeability in a dose-dependent manner. Pretreatment with NECA (10-1000 nmol/kg, i.v.) but not adenosine (100 nmol/kg i.v.), R-PIA (100 nmol/kg, i.v.) or APNEA (100 nmol/kg, i.v.) inhibited microvascular leakage produced by capsaicin aerosol (3 x 10(-5) M) in a dose-dependent manner. However, NECA (10-100 nmol/kg, i.v.) failed to inhibit substance P aerosol (10(-4) M)-induced extravasation of the dye. These findings suggest that stimulation of adenosine A 3 receptors produces airway vascular permeability, and that A 2 receptors inhibit neurogenic plasma extravasation, presumably by inhibiting the release of tachykinins from sensory nerves.
Yamawaki
I
I
First Department of Medicine, Tokyo Women's Medical College, Japan.
Tamaoki
J
J
Takeda
Y
Y
Nagai
A
A
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology*; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008297:Male; D009475:Neurons, Afferent / Q000378:metabolism; D058906:Purinergic P1 Receptor Agonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D018047:Receptors, Purinergic P1 / Q000502:physiology; D013373:Substance P / Q000494:pharmacology; D015320:Tachykinins / Q000378:metabolism; D014132:Trachea / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
C086112:N(6)-2-(4-aminophenyl)ethyladenosine; D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1; D015320:Tachykinins; D014665:Vasodilator Agents; C047235:N-(1-methyl-2-phenylethyl)adenosine; D013373:Substance P; D019830:Adenosine-5'-(N-ethylcarboxamide); D000241:Adenosine; D002211:Capsaicin