Comparisons of responses by planarian to micromolar to attomolar dosages of morphine or naloxone and/or weak pulsed magnetic fields: revealing receptor subtype affinities and non-specific effects

PURPOSE

The behavioral responses of planaria to the exposures of a range of concentrations of morphine (μM to attoM) or the μ-opiate antagonist naloxone or to either of these compounds and a burst-firing magnetic field (5 μT) were studied.

MATERIAL AND METHODS

The locomotor velocity (LMV) of planaria was measured after individual worms were exposed to increasing concentrations from attomolar to micromolar of morphine or naloxone, physiologically patterned magnetic fields or a combination of the two.

RESULTS

Compared to spring water controls, the 2-hour exposure to the patterned magnetic field before measurement reduced activity by about 50% which was comparable to the non-specific effects of morphine and naloxone across all dosages except 1 attomolar that did not differ from spring water. The specific dosage of 100 nM produced additional marked reduction in activity for planaria exposed to either morphine or naloxone while only 1 pM of morphine produced this effect.

CONCLUSION

The results support the presence of at least two receptor subtypes that mediate the diminished activity effects elicited by morphine specifically and suggests that exposure to the specifically patterned magnetic field produces a behavioral suppression whose magnitude is similar to the 'dose independent' effects from this opiate.

Intermittent exposures to nanoTesla range, 7 Hz, amplitude-modulated magnetic fields increase regeneration rates in planarian

PURPOSE

To discern if physiologically and naturally-patterned electromagnetic fields presented with base frequencies of 7 Hz within the 100 nT range could facilitate regeneration in planarian similar to microTesla, 60 Hz fields.

METHODS

In two separate experiments planarian were decapitated and exposed to either 140 or 400 nT peak amplitude-modulated 7 Hz magnetic fields for 6 min once per hour, 8 h per night for 5 days. Daily regeneration rates and movement velocities (cm/min) were measured.

RESULTS

The planarian exposed to either intensity magnetic field exhibited faster regeneration of photoreceptors and auricles compared to sham field and reference groups. The magnetic field exposure accommodated 50% of the variance during the faster growth days.

CONCLUSIONS

Naturally-patterned, intermittently-presented weaker electromagnetic fields may produce enhanced regeneration rates in flat worms similar to those observed for 60 Hz, higher intensity fields.