Neurogenic mechanisms in control of the rabbit iris sphincter muscle

Investigation of the specificity of FK 888 as a tachykinin NK1 receptor antagonist

“…The iris sphincter muscle of the rabbit and the vas deferens of the guinea-pig were dissected out and each was mounted vertically in a perspex holder in modified Krebs solution of the following composition (mM): NaCl 133, NaHCO3 16.3, KCI 4.7, MgCl2 1.0, NaH2PO4 1.4, CaCl2 2.5 and glucose 7.8 (Stjernquist et al, 1983;Wahlestedt et al, 1985). The preparations were stretched with a force of 1.5 mN (iris sphincter) or 5 mN (vas deferens).…”

Capsaicin enhances the non‐adrenergic twitch response of rat vas deferens

“…In guinea-pig taenia coli, Cap releases an unknown mediator from sensory neurones, which in turn stimulates cholinergic nerves of the myenteric plexus (SzolcsAnyi & Barth6, 1979). The Cap-induced contractions of guinea-pig trachea (Szolcsdnyi & Barth6, 1982) and ureter (Hua & Lundberg, 1986), rat urinary bladder (Maggi et al, 1985;Santicioli et al, 1986) and rabbit sphincter pupillae (Wahlestedt et al, 1985) and the Cap-induced positive inotropic response of guinea-pig atria (Lundberg et al, 1984) have been assumed to be mediated by some peptides released from sensory nerve endings. In addition to these stimulatory effects, Cap is also reported to inhibit the motility of rat ureter by releasing a neuropeptide from sensory nerve endings (Maggi et al, 1986c) and to cause relaxation of rat duodenum by activating an intramural inhibitory non-adrenergic, non-cholinergic mechanism (Maggi et al, 1986a,b).…”

(±)‐CP‐96,345, a selective tachykinin NK1 receptor antagonist, has non‐specific actions on neurotransmission

“…In the presence of 106 M atropine and 5 x 10-6 M guanethidine, the contractile response of the rabbit iris sphincter to electrical stimulation (20 Hz, 25 V, 10 s) is mediated by tachykinins (Wahlestedt et al, 1985). ( Also, electrical stimulation (3 Hz, 25 V, 3 s) of the atropinized guinea-pig taenia coli induces a contractile response that is mediated by tachykinins (Leander et al, 1981).…”

“…The animals were killed by a blow on the neck and exsanguinated. The iris sphincter muscle of the rabbit and the vas deferens and seminal vesicle of the guinea-pig were prepared and mounted vertically on a Perspex holder in a 8 ml organ bath as described elsewhere (Stjernquist et al, 1983;Wahlestedt et al, 1985). One end of the preparation was attached to a rigid support and the other to a Grass FT03 force displacement transducer.…”

“…The preparation was stretched with a force of 1.5 mN (iris sphincter) or 5 mN (vas deferens and seminal vesicle). The modified Krebs solution (Wahlestedt et al, 1985) was bubbled with a gas mixture of 7% CO2 in 02 giving a pH of 7.2-7.3 at 37°C.…”