Visual evoked potentials animal studies

Safety. Animal studies have shown that ranibizumab is a safe agent for intravitreal injection. In cynomolgus monkeys, intravitreal injections of 500 pg of ranibizumab at two-week intervals in a laser-induced CNV model (13) or in normal monkey eyes did not show any significant adverse effects (14). However, mild side effects of the injections were seen. All eyes treated with ranibizumab developed acute anterior chamber inflammation within 24 hours of the first intravitreal injection (13). In contrast, eyes injected with vehicle alone showed minimal or no inflammation. The inflammation resolved within one week, and the inflammatory response was less pronounced after subsequent intravitreal ranibizumab injections. Also, animal studies have shown that ranibizumab has no effect on electroretinography, including visually evoked potentials. 

The effects of lead exposure on visual evoked potentials have been studied in man and animals, but the results of these studies are quite inconsistent. Flash evoked potentials (FEP) have been used in animals, whereas pattern-reversal visual evoked potentials (PREP) have been used in humans. Fox et al (1977) reported increased latencies, Feeney ei ah (1979) found decreased latency, and Winneke (1979) found no latency differences in lead-exposed rats compared with controls. Similar differences were noted in FEP amplitude measures Winneke reported depressed amplitudes, but Fox et al (1979) found increased amplitude recovery (cortical excitability) to paired flashes in lead-exposed rats relative to controls. Fox et al added to the confusion by interpreting the increased latencies as evidence of decreased CNS recovery (1977) and the amplitude effects as evidence of increased CNS recovery (1979). Both Fox et al reports, moreover, were based on the same animals in the same experiment ... 

The focus on polyneuropathy in 14 studies has usurped studies of central nervous system (CNS) functions except for one showing increased latencies of visual and auditory evoked potentials. Neurophysiological and psychological assessments show narcotic effects that match those in animals. Until restricted from foods n-hexane was used to extract oil from soybean meal and exposed US workers. They had headache, dysesfliesia, insomnia, somnolence and memory loss but testing for appraise brain damage was not done. 

The International Association for the Study of Pain (lASP) has defined pain as an unpleasant sensory and emotional experience that is evoked by actual or potential noxious (i.e. tissue-damaging) stimuli or by tissue injury. Normally, pain is the subjective result of nociception. Nociception is the encoding and processing of noxious stimuli in the nervous system. It can be objectively measured with various techniques, i.e. with electrophysiological recordings. By contrast, pain as a subjective experience can be verbally or visually described by humans, and it cannot be measured objectively However, animals (as well as humans) show reflex responses to acute noxious stimuh, which can be assessed for the relationship between nociception and pain. 

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