Differential effects of cathinone compounds and MDMA on body temperature in the rat, and pharmacological characterization of mephedrone-induced hypothermia.

BACKGROUND AND PURPOSE: Recreational users report that mephedrone has similar psychoactive effects to 3,4-methylenedioxymethamphetamine (MDMA). MDMA induces well-characterized changes in body temperature due to complex monoaminergic effects on central thermoregulation, peripheral blood flow and thermogenesis, but there are little preclinical data on the acute effects of mephedrone or other synthetic cathinones. EXPERIMENTAL APPROACH: The acute effects of cathinone, methcathinone and mephedrone on rectal and tail temperature were examined in individually housed rats, with MDMA included for comparison. Rats were killed 2 h post-injection and brain regions were collected for quantification of 5-HT, dopamine and major metabolites. Further studies examined the impact of selected α-adrenoceptor and dopamine receptor antagonists on mephedrone-induced changes in rectal temperature and plasma catecholamines. KEY RESULTS: At normal room temperature, MDMA caused sustained decreases in rectal and tail temperature. Mephedrone caused a transient decrease in rectal temperature, which was enhanced by α(1) -adrenoceptor and dopamine D(1) receptor blockade, and a prolonged decrease in tail temperature. Cathinone and methcathinone caused sustained increases in rectal temperature. MDMA decreased 5-HT and/or 5-hydroxyindoleacetic acid (5-HIAA) content in several brain regions and reduced striatal homovanillic acid (HVA) levels, whereas cathinone and methcathinone increased striatal HVA and 5-HIAA. Cathinone elevated striatal and hypothalamic 5-HT. Mephedrone elevated plasma noradrenaline levels, an effect prevented by α-adrenoceptor and dopamine receptor antagonists. CONCLUSIONS AND IMPLICATIONS: MDMA and cathinones have different effects on thermoregulation, and their acute effects on brain monoamines also differ. These findings suggest that the adverse effects of cathinones in humans cannot be extrapolated from previous observations on MDMA.

Dispersion of gases in atomic iodine lasers at 1.315 microm.

A cw atomic iodine photolytic laser at 1.315 microm was used for the first time to measure the refractivities (polarizabilities or Gladstone-Dale constants) of He, H(2)O, N(2), O(2), Ar, CO(2), O(3), Cl(2), SF(6), ICl, CF(3)I, I(2), and n-C(3)F(7)I. For comparison with previous measurements, the refractivities were also obtained at 4579, 4880, 5145, and 6328 A. Excellent agreement at these wavelengths supports the validity of these newly reported results. The data presented are useful in the development of a near-diffraction-limited laser beam for any atomic iodine laser at 1.315 microm.