Behavioral characterization of the excitatory and desensitizing effects of intravesical capsaicin and resiniferatoxin in the rat.

This study characterized the excitatory (nociceptive) and desensitizing (antinociceptive) properties of the natural pungent substances, capsaicin (CAP) and resiniferatoxin (RTX) instilled in the bladder (intravesical, i.ves.) via an indwelling cannula in awake, freely moving rats.

Evidence for a single functional opioid delta receptor subtype in the mouse isolated vas deferens.

The identification of opioid delta receptor subtypes in mouse brain led to the investigation of the nature of the opioid delta receptors in the mouse isolated vas deferens in vitro. Noncumulative concentration-effect curves were constructed for DPDPE (delta 1 agonist) and [D-Ala2, Glu4]deltorphin (delta 2 agonist) in control tissues, or in tissues which had been incubated with either [D-Ala2, Leu5, Cys6] enkephalin (DALCE) (noncompetitive delta 1 antagonist) or 5'-naltrindole isothiocyanate (5'-NTII) (noncompetitive delta 2 antagonist). Incubation of the tissues with DALCE, under either oxygenated or nonoxygenated conditions, did not alter the concentration-effect curves for either agonist.