PT  - JOURNAL ARTICLE
AU  - Too, H P
AU  - Unger, W G
AU  - Hanley, M R
TI  - Evidence for multiple tachykinin receptor subtypes on the rabbit iris sphincter muscle.
DP  - 1988 Jan 01
TA  - Molecular Pharmacology
PG  - 64--71
VI  - 33
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/33/1/64.short
4100  - http://molpharm.aspetjournals.org/content/33/1/64.full
SO  - Mol Pharmacol1988 Jan 01; 33
AB  - The actions of mammalian tachykinins (substance P, substance K/neurokinin a, neuromedin K/neurokinin b) and non-mammalian tachykinins (eledoisin, kassinin, physalaemin) were compared on the rabbit pupillary sphincter. All acted as direct spasmogens with potencies in the order: eledoisin greater than physalaemin = neurokinin b = substance P greater than kassinin greater than neurokinin a. However, their actions could be divided into at least two categories on the basis of similar kinetics of contractions, differential sensitivity to the tachykinin antagonist (D-Arg1, D-Pro2, D-Trp7,9, Leu11) substance P and specific cross-protection against phenoxybenzamine inactivation by structurally related tachykinins. The relationship between these observations and the suggested "P" and "E" subtypes of tachykinin receptors is discussed.