F W Foong

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In barbiturate anaesthetized cats, tonic inhibition of the excitation of lumbar dorsal horn neurones by impulses in unmyelinated primary afferents was measured by reversibly cooling the spinal cord at the thoraco-lumbar junction. Tonic inhibition was reduced by microinjection of the GABA analogue, piperidine-4-sulphonic acid (2.5 nM in 0.5 microliter)(More)
Single neuronal responses induced by micro-application of bradykinin solution to the tooth pulp of the rabbit were recorded in the subnucleus reticularis dorsalis and trigeminal subnucleus caudalis and characterized by intermittent episodes of paroxysmal activities. Carbamazepine, the primary agent for trigeminal neuralgia, suppressed such a paroxysmal(More)
In barbiturate anaesthetized cats, dorsal column stimulation inhibited ascending volleys recorded in the antero-lateral spinal fasciculus from electrical stimulation of the contralateral tibial nerve and the excitation of neurones of the dorsal horn by noxious heating of the skin. The inhibition was non-selective. Intravenous bicuculline (0.2-0.6 mg/kg)(More)
The influence of naloxone (a narcotic antagonist), bicuculline (a GABA antagonist), phentolamine (an alpha-blocking agent), propranolol (a beta-adrenergic blocking agent), haloperidol (a dopaminergic blocking agent), methysergide (a serotonergic blocking agent) and atropine (a muscarinic blocking agent), on the antinociceptive effects induced by(More)
Ventral root reflexes and ascending volleys to stimulation of group I muscle afferents, large diameter cutaneous afferents and unmyelinated primary afferents were examined in barbiturate anaesthetized spinal cats. Intravenous naloxone (0.05-0.10 mg/kg) increased reflexes to stimulation of all primary afferent types but of the ascending volleys, only those(More)
In barbiturate anaesthetized cats, electrical stimulation in the periaqueductal grey (PAG) selectively inhibited the excitation of multireceptive dorsal horn neurons by noxious heating of the skin or by electrical stimulation of unmyelinated primary afferents. Intravenous methysergide (0.2-1.0 mg/kg) had opposing effects on uninhibited responses, increasing(More)
Intracisternal injections of carbamazepine produced a rapid and dose-dependent suppressive effect on the biting-like response induced by microapplication of bradykinin onto the tooth pulp (ED50: 2.62 micrograms/rat). Thus, the medullary dorsal horn is probably one of the primary sites for the antinociceptive activity of carbamazepine.
Using freely moving and conscious rats, the antinociceptive effects of microinjections of carbamazepine, into the periaqueductal gray (PAG), nucleus reticularis paragigantocellularis (NRPG) and nucleus raphé magnus (NRM) on the biting-like responses induced by bradykinin applied to the tooth pulp, were investigated to determine the primary site of action of(More)
In the spinal cord of the barbiturate anaesthetized cat, D-phenylalanine (DPA) depressed spontaneous and amino acid-induced firing of multireceptive dorsal horn neurones. The excitation of these neurones by noxious and non-noxious cutaneous stimuli was non-selectively depressed by DPA. DPA did not potentiate the depressant action of methionine enkephalin on(More)
Aversive (nociceptive) biting-like responses induced by micro-application of bradykinin solution onto rat tooth pulp were dose-dependently suppressed by non-narcotic drugs such as baclofen and lidocaine as well as carbamazepine and phenytoin, which are employed for clinical treatment of trigeminal neuralgia. The potency order of these drugs on a molar basis(More)