The in vivo pharmacological profile of a 5-HT1 receptor agonist, CP-122,288, a selective inhibitor of neurogenic inflammation.
1. The aim of the present study was to investigate the in vivo pharmacological profile of CP-122,288, an indole-derivative with a conformationally restricted N-methylpyrrolidinyl basic side chain in the C-3 position. This C-3 substituent structurally differentiates CP-122,288 from the 5-HT1D receptor agonist sumatriptan, which possesses an N,N-dimethylaminoethyl group. [Formula: see text] 2. When administered prior to electrical stimulation of the trigeminal ganglion, CP-122,288 (0.3-300 ng kg-1, i.v.) produced a dose-related inhibition of plasma protein extravasation in rat dura mater (minimum effective dose, MED, 3 ng kg-1 i.v., P < 0.05; maximal inhibition of plasma extravasation at 30 ng kg-1 i.v., P < 0.01). Sumatriptan produced a similar inhibition of plasma leakage in the dura, but at much higher dose levels (MED, 100 micrograms kg-1 i.v., P < 0.05). Thus, CP-122,288 is of the order of 10(4) fold more potent than sumatriptan. 3. At all doses tested, CP-122,288 did not inhibit plasma protein extravasation measured in extracranial tissues such as the lower lip, eyelid, and conjunctiva. 4. In a separate series of studies in the anaesthetized rat, CP-122,288 (0.003-3 micrograms kg-1 i.v.) produced no change in either heart rate or mean arterial blood pressure, thus demonstrating that doses of CP-122,288 which inhibit plasma protein leakage in rat dura, are devoid of hemodynamic effects. 5. Following a 5 min period of electrical stimulation of the trigeminal ganglion, a 20 min period of sustained neurogenically-driven plasma extravasation, occurring in the absence of electrical stimulation, was initiated. By administration of the compound 5 min after completing the phase of electrical stimulation, this protocol permitted the evaluation of the activity of CP-122,288 on an ongoing and established inflammatory event. CP-122,288 (30 and 300 ng kg-1, i.v., P < 0.01 and P < 0.05, respectively) produced a complete inhibition of plasma protein leakage which was consistent with its effects when administered prior to trigeminal ganglion stimulation. 6. In the anaesthetized dog, CP-122,288 and sumatriptan, at 1-300 micrograms kg-1, i.v., produced a dose-dependent reduction in carotid arterial blood flow and coronary arterial diameter. These data demonstrate that sumatriptan inhibits neurogenic inflammation in the rat (MED, 100 micrograms kg-1, i.v.), and produces vasoconstriction in the dog, over a similar dose-range. Interestingly, doses of CP-122,288 that inhibit neurogenic inflammation in rat dura mater (0.3-300 ng kg-1) were demonstrated to be devoid of vasoconstrictor activity in either the carotid or coronary vascular beds of dog. 7. These data demonstrate that in the rat, CP-122,288 is a highly potent and selective inhibitor of neurogenic inflammation in intracranial tissues, at doses which are devoid of vasoconstrictor activity in dog. Potentially, CP-122,288 may be of use for the acute treatment of migraine, without the risk of cardiovascular side-effects.
Gupta
P
P
Pfizer Central Research, Department of Discovery Biology, Sandwich, Kent.
Brown
D
D
Butler
P
P
Ellis
P
P
Grayson
K L
KL
Land
G C
GC
Macor
J E
JE
Robson
S F
SF
Wythes
M J
MJ
Shepperson
N B
NB
D000758:Anesthesia; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004388:Dura Mater / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D006439:Hemodynamics / Q000187:drug effects; D007249:Inflammation / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013045:Species Specificity; D018170:Sumatriptan / Q000031:analogs & derivatives* / Q000494:pharmacology; D012668:Trigeminal Ganglion / Q000187:drug effects / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011759:Pyrrolidines; D017366:Serotonin Receptor Agonists; C085263:CP 122288; D018170:Sumatriptan