ABSTRACT
This study aimed to evaluate the antinociceptive effect of sulphated polysaccharide from the marine algae Hypnea pseudomusciformis (PLS) using rodent models of orofacial pain. Acute pain was induced by formalin, capsaicin, cinnamaldehyde, acidified saline or glutamate (cutaneous modes) and hypertonic saline (corneal model). In one experiment, animals were pretreated with ruthenium red, glibenclamide, naloxone, L-NAME, methylene blue or ketamine to investigate the mechanism of antinociception. In another experiment, animals pretreated with PLS or saline were submitted to the temporomandibular joint formalin test. In yet another, animals were submitted to craniofacial pain induced by mustard oil. Motor activity was evaluated with the open-field test. Cytotoxicity and antioxidant activities were also assessed. Pre-treatment with PLS significantly reduced nociceptive behavior associated with acute pain. Antinociception was effectively reduced, but not inhibited, by ruthenium red and ketamine. L-NAME and glibenclamide enhanced the PLS effect. PLS antinociception was resistant to methylene blue, naloxone and heating. PLS presented no cytotoxicity or antioxidant properties. Our results confirm the potential pharmacological relevance of PLS as an inhibitor of orofacial nociception in acute pain probably mediated by glutamatergic, nitrergic, TRPs and K + ATP pathways.
Subject(s)
Analgesics/pharmacology , Cyanobacteria/classification , Facial Pain/drug therapy , Polysaccharides/pharmacology , Acute Pain/drug therapy , Animals , Disease Models, Animal , Male , Mice , Nociception/drug effects , Pain Measurement/methods , Rats , Rats, Wistar , RodentiaABSTRACT
This study aimed to develop and to evaluate the antinociceptive effect of a drug delivery system containing (-)-α-bisabolol (BISA). Nanocapsules containing BISA (BISA-NC) were prepared using acetylated galatomannan. Particle size distribution was determined by atomic force microscopy, zeta potential measurement and photon correlation spectroscopy. Corneal nociception was induced by topical application of 5M NaCl and the nociceptive behavior was characterized by eye wiping in mice. Molecular docking was conducted on the TRPV1 channel. Nanocapsules showed mean particle sizes between 94.44 and 105.44nm and the zeta potential of was -1.34mV. Animals pretreated with BISA-NC (200mg/mL) had a significant reduction (**p<0.01) in the number of nociceptive behaviors. Docking study indicated an interaction between BISA and TRPV1. This study indicates that BISA-NC may be useful for producing eye drops for the treatment of ocular pain.
