DR. TOWET PHILEMON KIPKEMOI

Abstract
Background: There are limited studies on the utilization of analgesics in testudines.
Management of pain in reptiles is by use of analgesics generally used in other vertebrate species. Evidently, some analgesics considered to be generally effective in
reptiles are not effective in certain reptile species.
Objective: The purpose of this study was to examine the effect of amitriptyline hydrochloride on nociceptive behaviour in Speke's hinge-back tortoise.
Methods: Twenty-four adult Speke-hinged tortoises weighing 500–700 g were used.
The effects of amitriptyline hydrochloride on nociception were evaluated using the
formalin, capsaicin and hot plate nociceptive tests. Amitriptyline was administered
intracoelomically at doses of 0.5, 1.0 and 3.0 mg/kg.
Results: The higher doses of amitriptyline hydrochloride caused an increase in nociceptive behaviour (time spent in hindlimb withdrawal) on the formalin and capsaicin
nociceptive tests, suggesting a potentiating effect. However, the doses used had no
significant change in nociceptive behaviour on withdrawal response in the hot plate
test.
Conclusions: The study showed that amitriptyline hydrochloride which is widely used
in management of neuropathic pain potentiates nociceptive effects in the formalin
and capsaicin nociceptive tests in the Speke's hinge-back tortoise. The hot plate test,
which previously has not been reported in these animals, gave results not in line
with the other tests and therefore more testing and validation of the test is required.
Amitriptyline modulates chemical and thermal pain differently

Abstract:
The study was designed to investigate the involvement of noradrenergic and serotonergic receptor systems in the modulation of formalin-induced pain-related behaviour in the Speke's hinged tortoise. Intradermal injection of 100 μL of formalin at a dilution of 12.5% caused pain-related behaviour (hindlimb withdrawal) that lasted for a mean time of 19.28 min (monophasic response). Intrathecal administration of clonidine (α2-adrenergic receptor agonist) and yohimbine (α2-adrenergic receptor antagonist) at a dose of 40 μg/kg and 37.5 μg/kg or 50 μg/kg, respectively, caused a highly significant reduction in the duration of the formalin-induced pain-related behaviour. The effect of clonidine was reversed by intrathecal administration of yohimbine at a dose of 26.7 μg/kg. The effect of yohimbine at a dose of 50 μg/kg was reversed by intrathecal injection of 20 μg/kg of the serotonergic receptor antagonist methysergide maleate. When performing antagonistic reactions, the administration of the antagonist was followed immediately by that of the agonist. The study indicates that for experimental purposes, intrathecal route of drug administration through the atlanto-occipital joint is effective in tortoises. The data also suggest that testudines have noradrenergic and serotonergic systems that appear to play a role in the modulation of pain in this species.

Little is known about analgesia in lower vertebrates such as the Speke’s hinged tortoise (Kinixy’s spekii), yet of late they are increasingly being adopted as pets. The effects of morphine (5, 7.5, 10 and 20 mg/kg), pethidine (10, 20, and 50 mg/kg) and naloxone (5 mg/kg) on nociception induced by the formalin test (12.5%, 100 μL) were studied in the Speke’s hinged tortoise. Formalin induced a monophasic limb retraction behavioural response and its duration was recorded. The behaviour lasted for 16.4 ± 0.8 min. Morphine (7.5, 10 and 20 mg/kg) and pethidine (20 and 50 mg/kg) induced significant decrease in the duration of limb retraction in the formalin test. The anti‐nociceptive effects were naloxone (5 mg/kg) reversible. The data suggest that the formalin test is a good test for studying nociception and anti‐nociception in tortoises and that the opioidergic system plays a role in the control of nociception in these animals.

Samples of burnt clay from kilns in various parts of the country were tested for their cementatious qualities and found to have high silica contents.Results showed that additing upto 40% of the cly to portland cement produced good binders for mass concre and plaster work,particularly for low cost housing.

Abstract
The antinociceptive effects of highly selective mu (DAMGO), delta (DPDPE) and kappa (U-50488 and U-69593) opioid agonists were evaluated following intraperitoneal (i.p.) administration in the naked mole-rat. A hot plate test set at 60 °C was used as a nociceptive test and the latency to the stamping of the right hind paw (response latency) was used as the end-point. DAMGO (5–10 mg/kg) and DPDPE (2.5–5 mg/kg) caused a naloxone-reversible significant decrease in the mean response latency. Subcutaneous injection of naloxonazine (20 mg/kg) 24 h prior to the administration of DAMGO (5 mg/kg) also blocked the reduction in the response latency observed when DAMGO was injected alone. On the contrary, U-50488 (2.5–5 mg/kg) or U-69593 (0.08 or 0.1 mg/kg) caused a naloxone-reversible significant increase in the mean response latency. These results showed that activation of mu or delta receptors caused hyperalgesia, whereas activation of kappa receptors caused antinociception in the hot plate test in naked mole-rat. This suggests that mu and delta receptors modulate thermal pain in a different way than kappa receptors in the naked mole-rat. It is not possible at the moment to point out how they modulate thermal pain as little is known about the neuropharmacology of the naked mole-rat.