Epilepsy-type convulsions

While normal cholinergic activity in the brain is essential for its normal functioning, strong activation of the cholinergic system in the CNS leads to loss of consciousness, to epilepsy-type convulsions, to muscular fasciculations (CNS-caused) and to down-regulation of the breathing center. 

ABSTRACT This review summarizes the literature on anticonvulsant activities of 334 medicinal plants used for the treatment of epilepsy and convulsive disorders in the indigenous system of medicine. Data on plants which have not yet been investigated for pharmacological activity are also presented. The details are presented in a tabular form. The data includes the plant part involved, the nature of the extract or fraction used and the names of active compounds and their structures wherever available. The terms used in ancient texts for various types of convulsive disorders are retained. The results of anticonvulsant activities of extracts, fractions and pure compounds isolated from the plants on various bioassays are also presented. 

Epilepsy (or epilepsies, since markedly different clinical entities exist) is a common neurological abnormality affecting about 1% of the human population. Epilepsy is a chronic, usually life-long disorder characterized by recurrent seizures or convulsions and usually, episodes of unconsciousness and/or amnesia. Table 32.1 illustrates the major types of epileptic seizures. Patients often exhibit more than one type. In most instances, the cause of the seizure disorder is not known (idiopathic epilepsy), although trauma during birth is suspected of being one cause. 

Epilepsy is a chronic neurologic disorder characterized by recurrent seizures.33 Seizures are episodes of sudden, transient disturbances in cerebral excitation that occur when a sufficient number of cerebral neurons begin to fire rapidly and in synchronized bursts.42 Depending on the type of seizure, neuronal activity may remain localized in a specific area of the brain, or it may spread to other areas of the brain. In some seizures, neurons in the motor cortex are activated, leading to skeletal muscle contraction via descending neuronal pathways. These involuntary, paroxysmal skeletal muscle contractions seen during certain seizures are referred to as convulsions. However, convulsions are not associated with all types of epilepsy, and other types of seizures are characterized by a wide variety of sensory or behavioral symptoms. 

Whereas the genetic and kindling models have been widely used to investigate possible neurotransmitter defects that cause different types of epilepsy, rodent models in which seizures are induced by electroshock, or by convulsant drugs such as pentylenetetrazol (also called pentetrazol, leptazol), picrotoxin or bicuculline, are mainly used in screening procedures to identify potential anticonvulsants. 

As noted, the barbiturates once were used extensively as sedative-hypnotic drugs, but except for certain specialized uses they now have been replaced by the safer benzodiazepines. Short-acting barbiturates still are used to produce anesthesia. Other current uses include emergency treatment of convulsions and prevention of seizures in persons with certain types of epilepsy (Perrine, 1996). 

ANTICONVULSANTS are drugs used to treat convulsions of various types, for instance, in drug or chemical poisoning, e.g. chlorpromazine, diazepam. However, these anticonvulsants are not necessarily effective or suitable for epilepsy. 

The main symptoms are seizures, often together with convulsions, but there are many types of epilepsy. 

Epilepsy is a category of CNS disorders characterized by recurrent transient attacks of disturbed brain function that result in motor (convulsive), sensory (seizure), and psychic episodes. Convulsions are not a consistent finding. Consciousness may be lost or altered depending on the type of disease (see Table 12-10). Seizures may be clonic, alternating muscle contraction and relaxation, or tonic (i.e., muscular tension). 

In epilepsy of the petit mal type usually momentary loss of eonsciousness prevails. This particular state is free of convulsions. However, occasionally blinking movements of the eyelids and jerking movements of the head or arms are observed. It is pertinent to mention here that this kind of epilepsy is more frequently seen in adoleseenee. 

It has the reputation for being the most effective succinimide analog in petit mal therapy. It acts by suppressing the EEC pattern of petit mal epilepsy perhaps by depression of the motor cortex and raising the convulsive threshold. Combined drug therapy with either phenobarbital or phenytoin sodium is common in cases where petit mal co-exists with grand mal or other types of epilepsy. 

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