Studies on Algesimetry by Electrical Stimulation of the Mouse Tail

Synthesis of a potent enkephalin analog, Tyr‐D‐Thr‐Gly‐Phe‐Δ3Pro‐NH2, and some of its biological activities

“…Elemental and amino acid analysis and physicochemical measurements (n.m.r., [a] D) for peptide intermediates were carried out by the Physical Chemistry Department of Hoffmann-La Roche Inc. Amino acid analyses were determined on a Beckman 121M amino acid analyzer. Solvent systems for thin-layer chromatography on silica gel G (Analtech, Inc.) or F-254 plates (Merck) were (A) 1-butano1:acetic acid:water (4: l : l ) , (B) 1 -butanol: ethyl acetate :acetic acid: water (1 : 1 : 1 : l), chloroform : methanol : acetic acid (85 : 10 : 5), (D) chloroform :methanol (50: 10) or (90: 10) and (E) pyridine:acetic acid: acetonitri1e:isopropanol: water (5.9: 1.9: 13.0: 13.0:66.2). Solvent fronts were run for 12-14cm and spots (30-5Opg loads) were visualized by ninhydrin or the fluorescarnine spray procedure (7) or by the chlorine-tolidine procedure (8,9).…”

“…Analgesic activity was determined by delivering painful electrical shocks through electrodes inserted into the tail of the mice using vocalization as the response (10). A train of 5 shocks of 20 millisecond duration delivered at 1 second intervals was used.…”

“…Compound IX (4.9g, 11.22mmol) was treated with 4N HCl in THF (150mL) for f h. Evaporation to dryness, trituration with dry ether and drying (KOH, Pz05) provided the tripeptide hydrochloride (3.75 g, 10.06 mmol, 89.7%).…”

“…Prep-500 instrument using a Prep-PAK C-18 cartridge equilibrated with 0.01 M acetic acid buffer adjusted to pH 4.5 by addition of Et,N. Elution proceeded via multiple step gradients of acetonitrile: 5 , 9,10,11,12, 50 and 9%. The product eluted at 10% modifier.…”

The history of pain measurement in humans and animals

“…In the first few decades of the 20th century, such methods were used to establish analgesic dose-response curves of opioids and aspirin (6)(7)(8), investigate intra-and inter-individual variability (5), circadian rhythmicity (7), spatial summation (9), counter-irritation (5), and even to demonstrate the effect of modulatory factors such as distraction (5). The first algesiometric techniques for laboratory animals were based on these human methods, with noxious stimuli aimed at easily accessible body parts such as the tail (10,11) and plantar hind paw (12,13). The von Frey filament test of mechanical sensitivity is used identically in human and non-human animals, with the exception of the range of filament force employed and the nature (verbal or non-verbal) of the response.…”